SYSTEM AND METHOD TO CONTROL A THREE-DIMENSIONAL (3D)

PRINTER

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 62/340,389, filed May 23, 2016 and titled "SYSTEM AND METHOD TO CONTROL A THREE-DIMENSIONAL (3D) PRINTER," U.S. Provisional Patent Application No. 62/340,421, filed May 23, 2016 and titled "SYSTEM AND METHOD TO CONTROL A THREE-DIMENSIONAL (3D) PRINTER," U.S. Provisional Patent Application No. 62/340,453, filed May 23, 2016 and titled "SYSTEM AND METHOD TO CONTROL A THREE-DIMENSIONAL (3D) PRINTING DEVICE," and U.S. Provisional Patent Application No. 62/340,436, filed May 23, 2016 and titled "SYSTEM AND METHOD TO CONTROL A THREE-DIMENSIONAL (3D) PRINTER," the contents of each of the aforementioned applications are expressly incorporated herein by reference in their entirety.

FIELD OF THE DISCLOSURE

[0002] The present disclosure is generally related to control of a three-dimensional (3D) printer device.

BACKGROUND

[0003] Improvements in computing technologies and material processing technologies have led to an increased interest in computer-driven additive manufacturing techniques, such as three-dimensional (3D) printing. Generally, 3D printing is performed using a 3D printer device that includes an extruder, one or more actuators, and a controller coupled to some form of structural alignment system, such as a frame. The controller is configured to control the extruder and the actuators to deposit material, such as a polymer-based material, in a controlled arrangement to form a physical object.

SUMMARY

[0004] In a particular implementation, a method includes obtaining model data representing a three-dimensional (3D) model of an object. The method also includes processing the model data to generate a set of commands to direct a 3D printer to extrude a material to form a physical model associated with the object. The set of commands is executable to cause an extruder of the 3D printer to deposit a first portion of the material corresponding to a first portion of the physical model, to clean, to purge, or to clean and purge the extruder after depositing the first portion of the material, and to deposit a second portion of the material after cleaning the extruder. The second portion of the material corresponds to a second portion of the physical model.

[0005] In another particular implementation, a method includes obtaining model data representing a three-dimensional (3D) model of an object. The method also includes processing the model data to generate a set of commands to direct a 3D printer to extrude one or more materials to form a physical model associated with the object. The set of commands is executable to cause a first extruder of the 3D printer to deposit a portion of a first material to form a first portion of the physical model and to, after depositing the portion of the first material, clean a second extruder of the 3D printer, purge the second extruder, or clean and purge the second extruder.

[0006] In a particular implementation, a three-dimensional (3D) printer device includes a first extruder configured to deposit a material on a deposition platform, an actuator coupled to at least one of the first extruder or the deposition platform, and a controller coupled to the actuator. The controller may be configured to cause the first extruder to deposit a first portion of the material corresponding to a first portion of a physical model. The controller may be configured to cause the first extruder to be cleaned, purged, or both, after the first extruder deposits the first portion of the material. The controller may be configured to cause the first extruder to deposit a second portion of the material after the first extruder is cleaned. The second portion of the material corresponds to a second portion of the physical model.

[0007] In another particular implementation, a three-dimensional (3D) printer device includes a first extruder configured to deposit a first material on a deposition platform, a second extruder configured to deposit a second material on the deposition platform, an actuator coupled to the first extruder, the second extruder, the deposition platform, or a combination thereof, and a controller coupled to the actuator. The controller is configured to cause the first extruder to deposit a first portion of the first material corresponding to a first portion of a physical model and to cause the second extruder to be cleaned, purged, or both, after the first extruder deposits the first portion of the first material.

[0008] In another particular implementation, a method includes depositing, using a first extruder of a three-dimensional (3D) printer device, a first portion of a first material corresponding to a first portion of a physical model of an object. The method also includes cleaning, purging, or cleaning and purging the first extruder after depositing the first portion of the first material. The method further includes, after cleaning the first extruder, depositing, using the first extruder, a second portion of the first material, the second portion of the first material corresponding to a second portion of the physical model.

[0009] In another particular implementation, a method includes depositing, using a first extruder of a three-dimensional (3D) printer device, a portion of a first material to form a first portion of a physical model. The method further includes, after depositing the portion of the first material, cleaning a second extruder of the 3D printer device, purging the second extruder, or cleaning and purging the second extruder.

[0010] In a particular implementation, a method includes obtaining model data representing a three-dimensional (3D) model of an object. The method also includes processing the model data to generate a set of commands to direct a 3D printer device to extrude a material to form a physical model associated with the object. The set of commands includes one or more first commands to cause relative motion of an extruder of the 3D printer device and a deposition platform of the 3D printer device during deposition a first portion of the material to form a portion of a first line, and after depositing a second portion of the material corresponding to a first end of the first line, to cause relative motion of the extruder and the deposition platform such that the extruder moves back along the first line while the extruder concurrently moves away from the deposition platform.

[0011] In another particular implementation, a method includes obtaining model data representing a three-dimensional (3D) model of an object. The method also includes processing the model data to generate a set of commands to direct a 3D printer device to extrude a material to form a physical model associated with the object. The set of commands includes one or more first commands to cause relative motion of an extruder of the 3D printer device and a deposition platform of the 3D printer device during deposition of a portion of the material corresponding to a line. The set of commands further includes one or more second commands to adjust an extrusion rate of the extruder based on an acceleration rate of the relative motion.

[0012] In a particular implementation, a three-dimensional (3D) printer device includes an extruder configured to deposit a material on a deposition platform, an actuator coupled to at least one of the extruder or the deposition platform, and a controller coupled to the actuator. The controller is configured to cause the extruder to deposit a first portion of the material corresponding to a first line, and after depositing a second portion of the material corresponding to a first end of the first line, to cause relative motion of the extruder and the deposition platform such that the extruder moves back along the first line while the extruder concurrently moves away from the deposition platform.

[0013] In another particular implementation, a three-dimensional (3D) printer device includes an extruder configured to deposit a material on a deposition platform, an actuator coupled to at least one of the extruder or the deposition platform, and a controller coupled to the actuator. The controller is configured to cause the actuator to cause relative motion of the extruder and the deposition platform during deposition of a portion of the material corresponding to a line and to adjust a flow rate of the extruder based on an acceleration rate of the relative motion.

[0014] In another particular implementation, a method includes moving an extruder of a three-dimensional (3D) printer device relative to a deposition platform of the 3D printer device during deposition a material to form a portion of a first line. The method also includes, after depositing a portion of the material corresponding to a first end of the first line, moving the extruder back along the first line and concurrently moving the extruder away from the deposition platform.

[0015] In another particular implementation, a method includes during extrusion of a material by an extruder of a three-dimensional (3D) printer device, moving the extruder relative to a deposition platform of the 3D printer device. The method also includes, during movement of the extruder, adjusting an extrusion rate of the extruder based on an acceleration rate of relative motion of the extruder and the deposition platform.

[0016] In a particular implementation, a method includes obtaining first model data specifying a first three-dimensional (3D) model of a first object and obtaining second model data specifying a second 3D model of a second object. The first model data indicates a location of the first 3D model relative to a model space and the second model data indicates a location of the second 3D model relative to the model space, where the second 3D model intersects the first 3D model in the model space. The method further includes processing the first model data and the second model data to generate machine instructions executable by a 3D printing device to generate a physical model of the first object, the physical model defining a void region to receive a physical instance of the second object.

[0017] In another particular implementation, a computer-readable storage device stores instructions that are executable by a processor to cause the processor to perform operations including obtaining first model data specifying a first three-dimensional (3D) model of a first object and obtaining second model data specifying a second 3D model of a second object. The first model data indicates a location of the first 3D model relative to a model space and the second model data indicates a location of the second 3D model relative to the model space, where the second 3D model intersects the first 3D model in the model space. The instructions further cause the processor to perform the operations of processing the first model data and the second model data to generate machine instructions executable by a 3D printing device to generate a physical model of the first object, the physical model defining a void region to receive a physical instance of the second object.

[0018] In another particular implementation, a computing device include a processor and a memory accessible to the processor. The memory stores instructions that are executable by the processor to cause the processor to perform operations including obtaining first model data specifying a first three-dimensional (3D) model of a first object and obtaining second model data specifying a second 3D model of a second object. The first model data indicates a location of the first 3D model relative to a model space and the second model data indicates a location of the second 3D model relative to the model space, where the second 3D model intersects the first 3D model in the model space. The instructions further cause the processor to perform the operations of processing the first model data and the second model data to generate machine instructions executable by a 3D printing device to generate a physical model of the first object, the physical model defining a void region to receive a physical instance of the second object.

[0019] In a particular implementation, a method includes obtaining model data specifying a three-dimensional (3D) model of an object. The method further includes processing the model data to generate a sliced model defining a plurality of layers to be deposited to form a physical model of the object. The plurality of layers include a first layer and a second layer, where the second layer is above and in contact with the first layer. The first layer includes a first region corresponding to a first material and a second region corresponding to a second material, and the second layer includes a third region corresponding to the first material and a fourth region corresponding to the second material. The method further includes generating machine instructions executable by a 3D printing device to deposit a portion of the first material corresponding to the first region and to the third region before depositing a portion of the second material corresponding to the second region and to the fourth region.

[0020] In another particular implementation, a method includes obtaining model data specifying a three-dimensional (3D) model of an object and generating first machine instructions executable by a 3D printing device to generate a first portion of a physical model of the object by depositing material using a syringe extruder. The first machine instructions indicate a first value of a pressure setting, the pressure setting indicating a pressure to be applied to the syringe extruder. The method also includes generating second machine instructions executable by the 3D printing device to generate a second portion of the physical model of the object by depositing material using the syringe extruder. The second machine instructions indicate a second value of the pressure setting.

[0021] In a particular embodiment, a computer-readable storage device stores instructions that are executable by a processor to cause the processor to perform operations including obtaining model data specifying a three-dimensional (3D) model of an object. The operations also include processing the model data to generate a sliced model defining a plurality of layers to be deposited to form a physical model of the object, the plurality of layers including a first layer and a second layer. The second layer is above and in contact with the first layer. The first layer includes a first region corresponding to a first material and a second region corresponding to a second material. The second layer includes a third region corresponding to the first material and a fourth region corresponding to the second material. The operations also include generating machine instructions executable by a 3D printing device to deposit a portion of the first material corresponding to the first region and to the third region before depositing a portion of the second material corresponding to the second region and to the fourth region.

[0022] In a particular embodiment, a computer-readable storage device stores instructions that are executable by a processor to cause the processor to perform operations including obtaining model data specifying a three-dimensional (3D) model of an object. The operations also include generating first machine instructions executable by a 3D printing device to generate a first portion of a physical model of the object by depositing material using a syringe extruder. The first machine instructions indicate a first value of a pressure setting. The pressure setting indicating a pressure to be applied to the syringe extruder. The operations also include generating second machine instructions executable by the 3D printing device to generate a second portion of the physical model of the object by depositing material using the syringe extruder. The second machine instructions indicate a second value of the pressure setting. [0023] In a particular embodiment, a computing device includes a processor and a memory accessible to the processor. The memory stores instructions that are executable by the processor to cause the processor to perform operations including obtaining model data specifying a three-dimensional (3D) model of an object. The operations also include processing the model data to generate a sliced model defining a plurality of layers to be deposited to form a physical model of the object. The plurality of layers include a first layer and a second layer, where the second layer is above and in contact with the first layer. The first layer includes a first region corresponding to a first material and a second region corresponding to a second material, and the second layer includes a third region corresponding to the first material and a fourth region corresponding to the second material. The operations also include generating machine instructions executable by a 3D printing device to deposit a portion of the first material corresponding to the first region and to the third region before depositing a portion of the second material corresponding to the second region and to the fourth region.

[0024] In a particular embodiment, a computing device includes a processor and a memory accessible to the processor. The memory stores instructions that are executable by the processor to cause the processor to perform operations including obtaining model data specifying a three-dimensional (3D) model of an object. The operations also include generating first machine instructions executable by a 3D printing device to generate a first portion of a physical model of the object by depositing material using a syringe extruder. The first machine instructions indicate a first value of a pressure setting, where the pressure setting indicates a pressure to be applied to the syringe extruder. The operations also include generating second machine instructions executable by the 3D printing device to generate a second portion of the physical model of the object by depositing material using the syringe extruder. The second machine instructions indicate a second value of the pressure setting.

[0025] In a particular embodiment, a three-dimensional (3D) printer device includes one or more extruders configured to deposit a first material and a second material on a deposition platform to generate a physical model of an object. The physical model includes a plurality of layers including a first layer and a second layer, where the second layer is above and in contact with the first layer. The first layer includes a first region corresponding to the first material and a second region corresponding to the second material, and the second layer includes a third region corresponding to the first material and a fourth region corresponding to the second material. The 3D printer device also includes an actuator coupled to the one or more extruders, the deposition platform, or a combination thereof. The 3D printer device also includes a controller coupled to the actuator. The controller is configured to cause the one or more extruders to deposit a portion of the first material corresponding to the first region and to the third region, after depositing the portion of the first material, to cause the one or more extruders to deposit a portion of the second material corresponding to the second region and to the fourth region.

[0026] In a particular embodiment, a three-dimensional (3D) printer device includes a syringe extruder configured to deposit a material on a deposition platform at a flowrate based on a pressure regulator setting. The 3D printer device also includes an actuator coupled to the syringe extruder, to the pressure regulator, to the deposition platform, or to a combination thereof. The 3D printer device further includes a controller coupled to the actuator. The controller is configured to cause the syringe extruder to deposit, based on a first value of the pressure regulator setting, a first portion of the material at a first flowrate to form a first portion of a physical model and to cause the syringe extruder to deposit, based on a second value of the pressure regulator setting, a second portion of the material at a second flowrate to form a second portion of the physical model.

[0027] In a particular embodiment, a method includes receiving machine instructions that enable a 3D printer to generate a physical model of an object. The physical model includes a plurality of layers that includes a first layer and a second layer, where the second layer is above and in contact with the first layer. The first layer includes a first region corresponding to a first material and a second region corresponding to a second material, and the second layer includes a third region corresponding to the first material and a fourth region corresponding to the second material. The method also includes depositing, based on the machine instructions, a portion of the first material

corresponding to the first region and to the third region. The method further includes, after depositing the portion of the first material, depositing, based on the machine instructions, a portion of the second material corresponding to the second region and to the fourth region.

[0028] In a particular embodiment, a method includes receiving first machine instructions associated with a first portion of a physical model of an object and second machine instructions associated with a second portion of the physical model. The first machine instructions indicate a first value of a pressure setting, where the pressure setting indicates a first pressure to be applied to a syringe extruder. The second machine instructions indicate a second value of the pressure setting, where the second value different from the first value. The method also includes depositing, using the syringe extruder of a three- dimensional (3D) printer device, a portion of a material at a first flowrate to form the first portion based on the first machine instructions. The method further includes depositing, using the syringe extruder, another portion of the material at a second flowrate to form the second portion based on the second machine instructions. The first flowrate is different from the second flowrate.

[0029] In another particular implementation, a method includes obtaining model data specifying a three-dimensional (3D) model of an object. The 3D model includes a first portion corresponding to a first material and a second portion corresponding to a second material. The method also includes processing the model data to generate a sliced model defining a plurality of layers to be deposited to form a physical model of the object. The method further includes identifying, based on the sliced model, an elongated feature extending between multiple layers of the plurality of layers and having, in each of the multiple layers, cross-sectional dimensions that satisfy a point-deposition criterion. The method also includes generating machine instructions executable by a 3D printing device to, for a first layer of the multiple layers, deposit a portion of the first material to define an opening associated with the elongated feature and deposit a portion of the second material within the opening according to a point-deposition technique.

[0030] In a particular implementation, a computer-readable storage device stores instructions that are executable by a processor to cause the processor to perform operations including obtaining model data specifying a three-dimensional (3D) model of an object. The 3D model includes a first portion corresponding to a first material and a second portion corresponding to a second material. The operations also include processing the model data to generate a sliced model defining a plurality of layers to be deposited to form a physical model of the object. The operations further include identifying, based on the sliced model, an elongated feature extending between multiple layers of the plurality of layers and having, in each of the multiple layers, cross-sectional dimensions that satisfy a point-deposition criterion. The operations also include generating machine instructions executable by a 3D printing device to, for a first layer of the multiple layers, deposit a portion of the first material to define an opening associated with the elongated feature and deposit a portion of the second material within the opening according to a point-deposition technique.

[0031] In a particular embodiment, a computing device includes a processor and a memory accessible to the processor. The memory stores instructions that are executable by the processor to cause the processor to perform operations including obtaining model data specifying a three-dimensional (3D) model of an object. The 3D model includes a first portion corresponding to a first material and a second portion corresponding to a second material. The operations also include processing the model data to generate a sliced model defining a plurality of layers to be deposited to form a physical model of the object. The operations further include identifying, based on the sliced model, an elongated feature extending between multiple layers of the plurality of layers and having, in each of the multiple layers, cross-sectional dimensions that satisfy a point-deposition criterion. The operations also include generating machine instructions executable by a 3D printing device to, for a first layer of the multiple layers, deposit a portion of the first material to define an opening associated with the elongated feature and deposit a portion of the second material within the opening according to a point-deposition technique.

[0032] In a particular embodiment, a three-dimensional (3D) printer device includes a first extruder configured to deposit a first material on a deposition platform and a second extruder configured to deposit a second material on the deposition platform. The 3D printer device also includes an actuator coupled to the first extruder, to the second extruder, to the deposition platform, or to a combination thereof. The 3D printer device also includes a controller coupled to the actuator. The controller is configured to cause the first extruder to deposit a portion of the first material to define an opening associated with an elongated feature of a physical model of an object. The elongated feature extends between multiple layers of a plurality of layers of the physical model and has, in each of the multiple layers, a cross-sectional dimension that satisfies a point-deposition criterion. The controller is further configured to cause the second extruder to deposit a portion of the second material to form a portion of the elongated feature according to a point- deposition technique.

[0033] In an embodiment, a method includes receiving machine instructions that enable generating a physical model of an object including an elongated feature, where the elongated feature extends between multiple layers of a plurality of layers of the physical model and has, in each of the multiple layers, a cross-sectional dimension that satisfies a point-deposition criterion. The method also includes depositing, using a first extruder of a three-dimensional (3D) printer device, a portion of a first material to define an opening associated with the elongated feature of the physical model. The method further includes depositing, using a second extruder of the 3D printer device, a portion of a second material to form a portion of the elongated feature according to a point-deposition technique, where the point-deposition technique causes the portion of the second material to be deposited within the opening.

[0034] The features, functions, and advantages that have been described can be achieved independently in various implementations or may be combined in yet other

implementations, further details of which are disclosed with reference to the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG. 1 is a block diagram that illustrates a system that includes a three- dimensional (3D) printing device, according to a particular embodiment;

[0036] FIGS. 2A, 2B and 2C illustrate extruding a material by a 3D printing device, according to particular embodiments;

[0037] FIGS. 3 A, and 3B illustrate extruding a material by a 3D printing device, according to particular embodiments;

[0038] FIG. 4 is a diagram that illustrates a particular embodiment of a method of slicing a 3D model to form commands to control a 3D printing device;

[0039] FIGS. 5, 6, 7, 8, 9, 10, 11, 12, 13, and 14 illustrate various stages during printing of a physical model of the 3D model of FIG. 4;

[0040] FIG. 15 is a flow chart of an example of a method that may be performed by the system of FIG. 1;

[0041] FIG. 16 is a flow chart of an example of a method that may be performed by the system of FIG. 1;

[0042] FIG. 17 is a flow chart of another example of a method that may be performed by the system of FIG. 1;

[0043] FIG. 18 is a flow chart of another example of a method that may be performed by the system of FIG. 1;

[0044] FIG. 19 is a flow chart of another example of a method that may be performed by the system of FIG. 1;

[0045] FIG. 20 is a flow chart of another example of a method that may be performed by the system of FIG. 1;

[0046] FIG. 21 is a flow chart of another example of a method that may be performed by the system of FIG. 1;

[0047] FIG. 22 is a flow chart of another example of a method that may be performed by the system of FIG. 1;

[0048] FIG. 23 is a block diagram that illustrates data flow among a computing device that includes a slicer application and a 3D printing device;

[0049] FIG. 24 is a diagram that illustrates a process of generating a sliced model;

[0050] FIG. 25 is a diagram that illustrates a particular embodiment of a method of slicing a 3D model to form commands to control a 3D printing device;

[0051] FIGS. 26-35 illustrate various stages during printing of a physical model of the 3D model of FIG. 25;

[0052] FIG. 36 is a flow chart that depicts an example of a method that may be performed by the system of FIG. 1;

[0053] FIG. 37 is a block diagram that illustrates a system that includes a three- dimensional (3D) printing device, according to a particular embodiment;

[0054] FIGS. 38A and 38B illustrate extruding material having particular line widths by a 3D printing device, according to particular embodiments;

[0055] FIGS. 39A and 39B illustrate extruding material having particular line heights by a 3D printing device, according to particular embodiments;

[0056] FIG. 40 illustrate extruding material to fill an opening according to particular embodiments;

[0057] FIG. 41 illustrate extruding material to fill an offset distance according to particular embodiments;

[0058] FIGS. 42-46 illustrate various stages during modeling, slicing and printing of a physical model;

[0059] FIG. 47 is a flow chart of an example of a method that may be performed by the system of FIG. 37;

[0060] FIG. 48 is a flow chart of another example of a method that may be performed by the system of FIG. 37;

[0061] FIG. 49 is a flow chart of another example of a method that may be performed by the system of FIG. 37;

[0062] FIG. 50 is a flow chart of another example of a method that may be performed by the system of FIG. 37;

[0063] FIG. 51 is a flow chart of another example of a method that may be performed by the system of FIG. 37; and

[0064] FIG. 52 is a flow chart of another example of a method that may be performed by the system of FIG. 37. DETAILED DESCRIPTION

[0065] A 3D printer may be a peripheral device that includes an interface to a computing device. For example, the computing device may be used to generate or access a 3D model of an object. In this example, a computer-aided design (CAD) program may be used to generate the 3D model. A slicer application may be to process the 3D model to generate commands that are executable by the 3D printer to form a physical model of the object. For example, the slicer application may generate G-code (or other machine instructions) that instruct the controller of the 3D printer when and where to move the extruder and provides information regarding 3D printer settings, such as extruder temperature, material feed rate, extruder movement direction, extruder movement speed, among others.

[0066] The slicer application may generate the G-code or machine instructions by dividing the 3D model into layers (also referred to as "slices"). The slicer application determines a pattern of material to be deposited to form a physical model of each slice. Generally, the physical model of each slice is formed as a series or set of lines of extruded material. The G-code (or other machine instructions), when executed by the controller of the 3D printer, cause the extruder to deposit a set of lines of the material in a pattern to form each layer, and one layer is stacked upon another to form the physical model. Layer stacking arrangements or support members can also be used to form lines of the material that are partially unsupported (e.g., arches).

[0067] The slicer application may also be able to generate the G-code or the machine instructions from 3D models of multiple objects. For example, the slicer application may be able to create one or more void regions in a physical model of a first object that correspond to a 3D model of a second object. The second object may be an electrical component or a circuit component, and the slicer application may process the multiple 3D models to generate the G-code or the machine instructions that allow inserting a physical instance of the second object into the physical model of the first object. Additionally, the slicer application may generate the G-code or the machine instructions to instruct a 3D printing device to form a physical model of a third object within a void region of the physical model of the first object. The third object may be formed by depositing conductive material. The third object may include or correspond to electrical or circuit components, such as electrical contacts, resistors, transistors, capacitors, inductors, etc. Thus, the slicer application may generate instructions that enable the 3D printing device to form a functional circuit within the physical model of the first object. By forming a functional circuit within the physical model, a 3D printing device may be able to print three dimensional electrical devices and components. Forming prototypes or products of electrical devices and components using a 3D printing device may be faster and less expensive than creating specific tool and die processes to manufacturer the prototypes or the products.

[0068] There are many ways that the slicer application can arrange the pattern of materials to be deposited to form each layer. Characteristics of a 3D print job may vary depending on how the slicer application arranges the pattern lines that make up each of the layers. For example, two different patterns of lines may have different printing characteristics, such as an amount of time used to print the physical model, an amount of material used to print the physical model, etc. As another example, two different patterns of lines may result in physical models that have different characteristics, such as interlay er adhesion, weight, durability, etc. Accordingly, different slicer applications or different settings or configurations of the slicer application can affect the outcome of a particular 3D print job.

[0069] Besides the arrangement of the pattern of materials, other factors can also affect print quality. For example, during extrusion, some materials have a tendency to clog or partially clog a nozzle of the extruder. As the nozzle begins to clog, the flow properties of the nozzle change. To illustrate, a decreased flow area of the nozzle can lead to forming lines that have decreased cross-sectional area, which can reduce print quality. Additionally, if a clog breaks loose during extrusion, the clog can be deposited as a clump or other line deformity. As another example, some materials may aggregate around the nozzle during extrusion to forms clumps that do not occlude the nozzle but can nevertheless lead to problems. These clumps of material can break loose during extrusion to cause clumps or other line deformities in the deposited material.

[0070] Accordingly, one method of improving print quality is to periodically or occasionally interrupt the extrusion process to clean the extruder, to purge the extruder, or both. The extruder can be cleaned by moving the extruder to a cleaning station that includes one or more brushes or scrapers. The brushes or scrapers may be passive such that the extruder is moved across the brushes or scrapers to remove excess material. Alternately, the brushes or scrapers may be active (e.g., moving linearly or rotating) to contact the extruder to remove excess material. The cleaning station may also include a waste catcher to catch and retain the removed excess material away from the object being printed. The waste catcher may also be used to purge material from the extruder. For example, material may be purged from the extruder when changing from using a first material to using a second material. As another example, if the material being deposited is reactive (e.g., cures after being mixed or upon exposure to air) some or all of the material may be purged when the extruder is cleaned to avoid curing of the material in the extruder.

[0071] In a particular embodiment, a 3D printer may include more than one print head or more than one extruder. Different types of extruders may be used to deposit different types of materials (e.g., physically or chemically distinct materials). For example, a filament-fed extruder may be used to deposit thermoplastic polymers, such as polylactic acid (PLA), acrylonitrile butadiene styrene (ABS) polymers, and polyamide, among others. Paste extruders, such as pneumatic or syringe extruders, may be used to deposit materials that are flowable at room temperature (or at a temperature controlled by the 3D printer). Examples of materials that may be deposited using paste extruders include silicone polymers, polyurethane, epoxy polymers. Paste extruders may be especially useful to deposit materials that undergo curing upon exposure to air or when mixed together (such as multi-component epoxies).

[0072] Some 3D printers include multiple extruders to improve print speed or to enable printing with multiple different materials. For example, a first extruder may be used to deposit a first material, and a second extruder may be used to deposit second material. In this example, the first and second materials may have different visual, physical, electrical, chemical, mechanical, and/or other properties. To illustrate, the first material may have a first color, and the second material may have a second color. As another illustrative example, the first material may have first chemical characteristics (e.g., may be a thermoplastic polymer), and the second material may have a second chemical

characteristics (e.g., may be a thermoset polymer). As yet another illustrative example, the first material may be substantially non-conductive, and the second material may be conductive. In this example, the first material may be used to form a structure or matrix, and the second material may be used to form conductive lines or electrical components (e.g., capacitors, resistors, inductors) of a circuit.

[0073] When a 3D printer uses multiple extruders to deposit multiple materials, determining when to switch between extruders can be challenging. For example, if an object being printed is formed of two different materials (e.g., a first material deposited by a first extruder and a second material deposited by a second extruder), a single layer of the object may include a region of the first material and a region of the second material. Switching extruders multiple times to print a single layer is time consuming and inefficient. Accordingly, the slicer application may be configured to reduce a number of tool swaps (i.e., changing from using the first extruder to using the second extruder, or vice versa). To illustrate, the region of the first material may be deposited before the region of the second material.

[0074] Further, in some implementations, regions of multiple layers of the first material may be deposited before the second material is deposited in regions of the multiple layers. For example, a first layer may include a first region associated with the first material and a second region associated with the second material. In this example, a second layer that is immediately adjacent to the first layer may include a third region associated with the first material and a fourth region associated with the second material. In this example, portions of the first material may be deposited to form the first region and the third regions. Subsequently, portions of the second material may be deposited to form the second region and the fourth region. Thus, some of the second material may be deposited on a layer below a highest layer of the first material that has been previously deposited.

[0075] In some instances, a 3D model may include a feature associated with one material that extends through multiple layers of the other material. For example, the feature may include a conductive feature (e.g. a wire formed of a conductive material) that is positioned such that it extends between multiple layers of a non-conductive material (e.g., a matrix material). In this example, the wire may have a relatively small cross-section in each layer. Conventional deposition techniques move an extruder laterally (e.g., in an X- Y plane) as material is extruded; however, due to the small cross-section of wires, and other extended features, lateral motion of the extruder may be inconvenient. In a particular embodiment, such extended features may be formed according to a point- deposition technique. To use the point-deposition technique, one or more layers of the matrix material may be deposited to form an opening (or hole). A second material (e.g., the conductive material) may be deposited in the opening according to the point- deposition technique. The point-deposition technique may control a flow rate and dwell time of the extruder such that enough of the second material is deposited to substantially fill the opening. If multiple layers of the matrix material are deposited before the second material is deposited, an end of the extruder may be positioned with the opening (e.g., below an upper layer of the matrix material). The extruder may begin extruding the second material, and the extruder may move vertically (e.g., along a Z-axis) relative to the physical model being formed. For example, a deposition platform may be moved away from the extruder. As another example, the extruder may be moved away from the deposition platform. Thus, multiple layers of the second material may be deposited together according to the point-deposition technique. Depositing multiple layers of the second material together may improve interlayer adhesion. Additionally, if the second material is conductive, depositing multiple layers of the second material together may improve electrical properties of a wire formed using the second material.

[0076] When a 3D printer uses multiple extruders to deposit multiple materials, one extruder may be idle (i.e., not extruding material) while another is depositing material. For example, while a first extruder is depositing a matrix material, a second extruder may be idle. Idle extruders may be particularly subject to clogging since flow of material through the extruder may reduce clogging. If the idle extruder becomes clogged, it can lead to reduced print quality as a result of clumps in material that is later deposited by the extruder.

[0077] Accordingly, to improve print quality, a print job may be periodically or occasionally interrupted to clean or purge an idle extruder. To illustrate, after a first extruder deposits a first portion of a first material to form part of a physical object, a second extruder (that was idle while the first extruder deposited the first portion of the first material) may be cleaned. Subsequently, the print job may be resumed. For example, the first extruder may deposit a second portion of the first material to form another part of a physical object. Alternately, the second extruder may deposit a second material, or a third extruder may deposit a third material.

[0078] In some implementations, the first extruder may also be cleaned while the print job is interrupted. For example, cleaning of the first extruder and of the second extruder may be scheduled so that both are cleaned when either one is to be cleaned.

[0079] In some implementations, cleaning operations may be encoded in the G-code or other machine instructions. For example, the slicer application may schedule cleaning operations for one extruder or for multiple extruders. In this example, the G-code or other machine instructions include a sequence of operations associated with printing the physical model (e.g., extrusion operations, extruder movement operations, etc.) and at least one cleaning operation is embedded with the sequence of operations associated with printing the physical model.

[0080] In other implementations, cleaning operations may be scheduled or implemented by the controller of the 3D printer. For example, the slicer application may provide G- code or other machine instructions that specify a sequence of operations associated with printing the physical model, and, during printing, the controller may interrupt execution of the sequence of operations to perform cleaning operations.

[0081] The cleaning operations may be performed based on an amount of material deposited. For example, the slicer application may determine a quantity of material that will be used to form a portion of the physical model, and the slicer application may insert a cleaning operation into the G-code or machine instructions when the quantity of material that will be used to form the portion satisfies a threshold. Alternately, the controller of the 3D printer may track the quantity of material that has been deposited and interrupt the printer to clean one or more extruders when the quantity of material that has been deposited satisfies a threshold. In other implementations, deposition time of an extruder, idle time of an extruder, or both may be determined or tracked to schedule cleaning operations.

[0082] Some materials begin curing (i.e., solidifying) upon exposure to air or upon mixing. For example, two-part epoxies include an epoxy resin and a hardening agent. After the epoxy resin and the hardening agent are mixed, the mixture begins to cure. When a 3D printer uses such materials, one or more extruders of the 3D printer may be cleaned or purged based on a time since mixing the materials (or a time since the materials were exposed to air). For example, if a material that cures after mixing is to be used, the slicer application may generate G-code (or other machine instructions) for mixing the materials. In this example, the slicer application may cause the materials to be mixed based on when the mixture will be needed during printing of the physical model. Additionally, the slicer application may track (e.g., by summing deposition time of all extruders of the 3D printer) when to schedule a cleaning operation or a purging operation to prevent the mixture from curing in the extruder. In another example, the G-code (or other machine instructions) include instructions for mixing the materials, and the controller of the 3D printer determines (e.g., based on a timer) when to schedule a cleaning operation or a purging operation to prevent the mixture from curing in the extruder.

[0083] The arrangement of the pattern of materials to be deposited to form each layer may be of particular concern for certain materials. For example, certain materials have a tendency to form blobs or other irregularly shaped deposits (sometimes referred to as "kisses") at the start of a line, the end of a line, or both. A kiss can cause an issue with layer stacking if a portion of the kiss extends above the layer on which it is deposited. A kiss can also, or in the alternative, cause an issue with line arrangement with the layer being printed if the kiss extends beyond the width of its line into an area associated with another line.

[0084] Slicing the 3D model in a manner that reduces line starts and stops can reduce the number of kisses in a physical model. The number of line starts and stops can be reduced by configuring the slicer application to use as few lines as possible (or as few lines as practical in view of other settings or goals) for each layer. For example, when a line extends to an edge of the layer, rather than ending the line, lifting the extruder head and moving to a new location for the next line, the slicer application may instruct the 3D printer to turn the line (e.g., in a U-turn) to continue the line in another direction.

[0085] The number of line starts and stops can also be reduced by extending lines between layers. For example, when a first layer is complete, rather than ending the line and lifting the extruder head to begin printing the next layer, the line may be extended to overlay a portion of the first layer to immediately begin printing a portion of the second layer. To illustrate, if the first layer is in a horizontal plane, the material forming the line may be deposited to form a vertical or oblique riser up to a plane of the second layer.

[0086] As another example, a first portion of a physical model may be formed by stacking multiple layers of material (e.g., a base layer and one or more additional layers at least partially overlaying the base layer) before moving the extruder head to a different location to form another portion of the base layer. In this example, the multiple layers may be stacked using a single continuous deposition step (e.g., with one start and one stop).

[0087] Another method that may be used to reduce kisses is to perform additional steps at the end of a line. For example, when a line ends, rather than ceasing extruder flow and lifting the extruder head, the extruder head may be caused to move backward (e.g., in a direction back along the line that was just deposited) as the extruder flow is stopped, as the extruder head is lifted, or both. Alternately, the extruder flow can be ceased before the line end is reached. After the extruder reaches the line end, the extruder head can be lifted and moved back along the line. By causing the extruder head to backtrack along the line with flow stopped or as flow stops, potential kiss at the line end can be smoothed out.

[0088] Yet another method that may be used to reduce kisses is to control extruder flow in a manner that accounts for acceleration of the extruder head. For example, pressure applied to the material being deposited, temperature of the material, filament feed rate, or a combination thereof, may be used to control a flow rate of material from the extruder. The G-code (or other machine instructions) may include settings for the temperature, the pressure, the filament feed rate, or a combination thereof. Additionally, the G-code (or other machine instructions) may include information indicating a velocity (e.g., speed and direction of travel) for movement of the extruder head during deposition. At the beginning of a line, the extruder head is not able to instantaneously achieve the indicated velocity. Rather, due to inertia and/or settings of the 3D printer, the extruder head velocity gradually increases to the indicated velocity. During this acceleration from a starting velocity to the indicated velocity, if the same extruder flow rate is used as is used when the extruder is at the indicated velocity, more material will be deposited at the beginning of the line than in the remainder of the line. A similar issue arises at the end of the line. That is, when the extruder approaches the end of a line, the extruder is not able to decelerate from the indicated velocity to an ending velocity (e.g., stopped)

instantaneously. Rather, the extruder head velocity gradually decreases to the ending velocity. During this deceleration (i.e., negative acceleration), if the same extruder flow rate is used as is used when the extruder is at the indicated velocity, more material will be deposited at the end of the line than in the remainder of the line. Accordingly, kisses or other line irregularities can be reduced by controlling the flow rate of the extruder based on an acceleration rate of the extruder.

[0089] FIG. 1 illustrates a particular embodiment of a system 100 that includes a 3D printer device 101 and a computing device 102. The 3D printer device 101 and the computing device 102 may be coupled via a communications bus 160, which may include a wired or wireless communications interface. The 3D printer device 101 is configured to generate physical models of objects based on a 3D model or commands based on model data.

[0090] In a particular embodiment, the computing device 102 includes a processor 103 and a memory 104. The memory 104 may include a computer readable storage device (e.g., a physical, hardware device, which is not merely a signal), such as a volatile or nonvolatile memory device. The computing device 102 may include a 3D modeling application 106. The 3D modeling application 106 may enable generation of 3D models, which can be used to generate model data 107 descriptive of the 3D models. For example, the 3D modeling application 106 may include a computer-aided design application.

[0091] The computing device 102 or the 3D printer device 101 includes a slicer application 108. The slicer application 108 may be configured to process the model data 107 to generate commands 109 that the 3D printer device 101 (or portions thereof) uses during generation of a physical model of an object represented by the model data 107. In the particular embodiment illustrated in FIG. 1, the commands 109 may include G-code commands or other machine instructions that are executable by the 3D printer device 101 (or a portion thereof). For model data (e.g., the model data 107) that includes one or more 3D models of multiple objects, the slicer application 108 may process the model data 107 to generate a single integrated model with one or more void regions that correspond to one or more objects of the multiple objects. The slicer application 108 may generate instructions to enable an electrical component (e.g., a non-printed component) to be inserted into a void region, to form (e.g., deposit conductive material) electrical or circuit components (e.g., electrical contacts, resistors, transistors, capacitors, inductors, etc.) in a void region, or both. The slicer application 108 is described in further detail with respect to FIGS. 23-25.

[0092] The computing device 102 may also include a communications interface 105 that may be coupled via the communication bus 160 to the 3D printer device 101. For example, the 3D printer device 101 may be a peripheral device that is coupled via a communication port to the computing device 102.

[0093] The 3D printer device 101 includes a frame 110 and support members 111 arranged to support various components at the 3D printer device 101. In particular embodiments, the 3D printer device 101 may include a deposition platform 112. In other embodiments, the 3D printer device 101 does not include a deposition platform 112 and another substrate or surface may be used for deposition. The 3D printer device 101 also includes one or more printheads. For example, in the embodiment illustrated in FIG. 1, the 3D printer device 101 includes a first printhead 113, a second printhead 114, and an Nth printhead 115. Although three particular printheads are illustrated in FIG. 1, in other embodiments, the 3D printer device 101 may include more than three printheads or fewer than three printheads. Each printhead 113-115 includes a corresponding extruder with an extruder tip. For example, the first printhead 113 includes a first extruder 130 having a first extruder tip 131, the second printhead 114 includes a second extruder 132 having a second extruder tip 133, and the Nth printhead 115 includes an Nth extruder 134 including an Nth extruder tip 135.

[0094] Each printhead 113-115 is coupled to receive a material that may be deposited to form a portion of a physical model of an object. For example, the first printhead 113 may be coupled to a first material container 119 that includes a first material 120. As another example, the second printhead 114 may be coupled to a second material container 121 that includes a second material 122. The Nth printhead 115 may be coupled to a mixer 127. The mixer 127 may be coupled to a first component container 123 and a second component container 125. The first component container 123 may be configured to retain a first component 124, such as a resin. In this example, the second container 125 may be configured to contain a second component 126, such as a hardening agent. In the example illustrated in FIG. 1, the first component container 123 and the second component container 125 are coupled to the mixer 127 to enable the mixer 127 to generate a mixture 128 that includes a portion of the first component 124 and a portion of the second component 126. The first component 124 and the second component 126 may be selected to begin hardening upon mixing. Thus, the mixture 128 may begin curing as soon as the mixer 127 has mixed the components.

[0095] Proportions of the components 124, 126 supplied to the mixer 127 may be controlled by a controller 141 of the 3D printer device 101. The controller 141 may also, or in the alternative, control one or more actuators 143 to move the deposition platform 112 relative to the printheads 113-115, to move the printheads 113-115 relative to the deposition platform 112, or both. For example, in a particular configuration, the deposition platform 112 may be configured to move in a Z direction 140. In this example, the printheads 113-115 may be configured to move in an X direction 138 and a Y direction 139 relative to the deposition platform 112. Thus, movement of one or more printheads 113-115 relative to the deposition platform 112 may involve movement of the deposition platform 112, movement of one or more of the printheads 113-115, or movement of both the deposition platform 112 and the printheads 113-115. In other examples, the deposition platform 112 may be stationary and one or more of the printheads 113-115 may be moved. In yet other examples, the one or more printheads 113-115 may be stationary and the deposition platform 112 may be moved.

[0096] The 3D printer device 101 of FIG. 1 also includes one or more cleaning stations 136, one or more purging stations 137, or both. The cleaning stations 136 may be configured to clean one or more extruder tips, such as the first extruder tip 131, the second extruder tip 133, the Nth extruder tip 135, or a combination thereof. In the examples illustrated herein, each extruder tip 131, 133, 135 may be associated with a corresponding cleaning station, as described further below. However, in other examples, one cleaning station may be used for multiple extruder tips 131, 133, 135. The cleaning station 136 may include a scraper, brushes, or other devices that are used to remove particulate or other foreign matter from the extruder tips 131, 133, 135. In some examples, the cleaning station 136 may be movable relative to the frame 110 or printheads 113-115. For example, the cleaning station 136 may move to the printheads 113-115 to clean the corresponding extruder tip rather than the printheads 113-115 moving to the cleaning station 136.

[0097] The purging station 137 may be configured to receive a material from one or more of the printheads 113-115 in order to purge an extruder of the printhead 113-115. For example, the mixture 128 may begin to cure upon mixing. Accordingly, the mixture 128, or a portion thereof, may be purged occasionally to avoid curing of the mixture 128 within the extruder 134 or within the mixer 127. As an example, when the Nth extruder 134 is purged, the Nth printhead 115 may be moved adjacent to or over the purge station 137, and at least a portion of the mixture 128 may be extruded by the extruder 134 into the purge station 137. The purge station 137 may be configured to be removable or replaceable such that after the mixture 128 cures in the purge station 137, the cured mixture 128 can be removed without damaging components of the 3D printer device 101. Other materials used by other extruders may be deposited in the purge station 137 occasionally. For example, the second material 122 may include a paste that begins to cure upon exposure to air. In this example, the second extruder 132 may be purged at the purge station 137 occasionally to avoid clogging the second extruder tip 133, the second extruder 132, or both. Further, the first material 120 may include a filament or other thermoplastic polymer, and the first material 120 may be occasionally purged at the purge station 137 in order to retain desirable properties of the filament, to avoid clogging the extruder 130, or both. When a printhead 113-115 is purged at the purge station 137, the printhead 113-115 may also be cleaned at the cleaning station 136 to prepare the printhead 113-115 for use.

[0098] The 3D printer device 101 may also include a memory 142 accessible to the controller 141. The controller 141 may include or have access to one or more timers 144, one or more material counters 145, or both. The material counters 145 may track a quantity of materials in the material containers 119, 121, 123, 125, a quantity of material in the mixer 127, a quantity of each material deposited to form a physical model of an object, etc. For example, during formation of a first physical model (or a portion of the first physical model), the first material 120 may be deposited by the first printhead 113. During formation of the first physical model, the material counter 145 may track a quantity of the first material 120 that has been deposited. The material counter 145 may also, or in the alternative, track a quantity of material remaining. To illustrate, during formation of the first physical model, while the first material 120 is being deposited, the material counter 145 may track a quantity of the first material 120 that remains in the first material container 119. As another example, when the mixture 128 is deposited to form a portion of the physical model, the material counter 145 may track a quantity of the mixture 128 remaining in the mixer 127. When the quantity of material remaining in the mixer 127 is below a threshold, the controller 141 may cause the mixture 128 to be purged at the purge station 137 and may cause the first component container 123 and the second component container 125 to provide the first component 124 and the second component 126, respectively, to the mixer 127 to generate a new mixture 128.

Alternatively, portions of the first component 124 and the second component 126 may be added to an existing mixture 128 in the mixer 127.

[0099] The timers 144 may track an amount of time associated with particular activities of the 3D printer device 101. For example, a first timer of the timers 144 may track a time since mixing the mixture 128. The time since mixing the mixture 128 may be used to determine when to purge the mixture 128. For example, the mixture 128 may be purged before a cure time associated with the mixture 128 is reached. The timers 144 may also, or in the alternatively, track how long a particular printhead 113-115 has been idle. For example, during deposition of the first material 120 to form a portion of a physical model, the second material 122 may sit idle in the second printhead 114 or in the second material container 121. Since the second material 122 may begin to cure upon exposure to air, the portion of the second material 122 exposed at the second extruder tip 133 may begin to cure, potentially causing a clog. Accordingly, based on the timers 144 indicating that the second printhead 114 has been sitting idle for a threshold amount of time, a print activity being performed by the 3D printer device 101 may be interrupted to move the second printhead 114 to the cleaning station 136, the purging station 137, or both, to remove a portion of the second material 122 from the second extruder 132 to avoid clogging the second extruder 132.

[00100] As another example, the timers 144 may indicate how long a particular extruder has been in use. For example, when the first extruder 130 is being used to deposit a portion of material corresponding to a physical object, the first extruder 130 may be cleaned periodically to remove excess material that occasionally aggregates around the first extruder tip 131. Thus, based upon the timers 144, a 3D printing operation being performed by the 3D printer device 101 may be interrupted, and the first extruder 130 may be moved to the cleaning station 136, to the purging station 137, or both, to clean the first extruder tip 131.

[00101] After cleaning of a particular extruder has been performed, the 3D printing operations may resume where they left off. For example, when the first extruder 130 was being used to form a portion of a physical model, and the timer 144 or the material counter 145 indicated cleaning was needed, the print activity may be interrupted, the first extruder 130 may be cleaned, purged or both, and then the printing activity may resume with the first extruder 130 depositing the first material to form a second portion of the physical object. Alternatively, cleaning operations may be scheduled based on the timers

144, the material counter 145, or both, such that the cleaning and/or purging operations occurs between uses of particular extruders. For example, while the first extruder 130 is in use to form a first portion of a physical model, the timers 144, the material counters

145, or both, may reach a value indicating that cleaning is needed. After the first operations being performed by the first extruder 130 is complete (e.g., when an end point associated with the first extruder 130 is reached), the cleaning operation may be performed. The cleaning operation may include cleaning and/or purging the first extruder 130, the second extruder 132, the Nth extruder, or a combination thereof. After the cleaning operation has been performed, printing operations may resume, for example, with the second extruder depositing the second material 122 to form a second portion of the 3D model of the physical object.

[00102] In a particular embodiment, the memory 142 includes cleaning and purging control instructions 147. The cleaning and purging control instructions 147 may include instructions (e.g., a cleaning sequence of instructions, a purging sequence of instructions, or both) that facilitate cleaning and purging of the printheads 113-115. For example, when the controller 141 determines that a cleaning operation is to be performed, the controller 141 may interrupt operations being performed at the 3D printer device 101 and execute the cleaning sequence of instructions of the cleaning and purging control instructions 147. As another example, when the controller 141 determines that a purging operation is to be performed, the controller 141 may interrupt operations being performed at the 3D printer device 101 and execute the purging sequence of instructions of the cleaning and purging control instructions 147.

[00103] In some implementations, the cleaning and purging control instructions

147 may include thresholds associated with the timers 144, thresholds associated with the material counters 145, or both. To illustrate, the thresholds may include a cure time associated with the mixture 128 or a threshold time that precedes the cure time at which the mixture 128 is to be purged and/or cleaned. As another example, the thresholds may include a downtime limit associated with one or more of the printheads 113-115. The downtime limit may be used to determine whether one or more of the printheads 113-115 should be cleaned based on a downtime of the particular printhead. As another example, the thresholds may include use time thresholds associated with the particular printhead 113-115. The use time thresholds may indicate how long a particular printhead 113-115 can be in use before cleaning and/or purging of the particular printhead 113-115 is needed. As another example, the thresholds may include material quantity thresholds that indicate how much material a particular printhead 113-115 can deposit before cleaning and/or purging of the particular printhead 113-115 is needed. In some implementations, the thresholds may be stored as part of the settings 150.

[00104] The cleaning and purging control instructions 147 may also include instructions that cause more than one printhead to be cleaned at a time. For example, when the timers 144 or the material counters 145 indicates that the first printhead 113 is to be cleaned, the cleaning and control instructions 147 may also cause the second printhead 114, the Nth printhead 115, or both, to be cleaned, so that multiple cleaning operations are performed concurrently or sequentially to reduce interruption to print operations.

[00105] The memory 142 may also include calibration data 148. The calibration data 148 may include information that indicates relative positions of the printheads 113- 115. In the particular example illustrated in FIG. 1, the printheads 113-115 may be independently movable by corresponding actuators 143 or may be movable together by one or more actuators 143. The calibration data 148 may indicate distances between printheads 113-115, extruder tips 131, 133, 135, or both. Additionally, or in the alternative, the calibration data 148 may include information about ramp up speeds associated with the actuators 143. For example, the ramp up speeds may indicate how quickly a particular printhead 113-115 can accelerate from stopped to a specified velocity. As another example, the calibration data 148 may include extrusion rates or deposition rates associated with one or more of the printheads 113-115 based on particular control parameters, such as temperature of the extruder or extruder tip, pressure applied to the extruder or extruder tip, a type of material being deposited, a material feed rate, or a combination thereof. For example, the calibration data 148 may include rheology data based on temperature associated with the first material 120, the second material 122, or the mixture 128. As another example, the calibration data 148 may include rheology data associated with the mixture 128 over time.

[00106] The memory 142 may also include test print data 151. The test print data

151 may be used to generate at least a portion of the calibration data 148. For example, the test print data 151 may include commands to generate one or more test print objects using multiple of the printheads 113-115. Positions, orientations, and other information about the test print objects may be measured after a test print is performed and the measurements may be used to adjust the calibration data 148. For example, the 3D printer device 101 may include a measurement device, such as a scanning device (not shown), that automatically measures the test print objects. Alternately, the test print objects may be manually measured and updated calibration data may be provided via a user interface (not shown) or via the computing device 102.

[00107] The memory 142 may also include end-of-line-technique instructions 149.

The end-of-line-technique instructions 149 include instructions that enable formation of line ends having a target width without undesired characteristics, such as bulges and blobs. Examples of end-of-line techniques are described further with reference to FIGS. 2A-2C and 3A-3B. The end-of-line-technique instructions 149 may be applied to commands provided by an external computing device, such as the computing device 102, in order to improve line ends associated with physical models printed by the 3D printer device 101. The end-of-line technique instructions 149 may include instructions to implement the technique described with reference to FIGS. 2C, instructions to implement the technique described with reference to FIGS. 3B, other end-of-line techniques, or a combination thereof.

[00108] Accordingly, the 3D printer device 101 enables use of multiple printheads

113-115 with multiple distinct materials, such as the first material 120, the second material 122, the mixture 128, or a combination thereof, to form physical models of 3D objects corresponding to model data 107. The 3D printer device 101 is able to improve printing outcomes by controlling cleaning and purging of the printheads 113-115 and by using improved end-of-line techniques. Further, the 3D printing device 101 is able to form a functional circuit within the physical model by creating void regions within the physical model of the object that contain physical instances of electrical or circuit components. Additionally, the 3D printing device 101 may be able to form the circuit within the physical model of the object by depositing electrically conductive material to form electrical or circuit components, such as electrical contacts, resistors, transistors, capacitors, inductors, etc., within the physical model and the void regions thereof.

[00109] FIGS. 2A-2C illustrate use of end-of-line deposition techniques. In FIG.

2A, an extruder 202 is illustrated depositing a material 204 on a substrate, such as the deposition platform 112. As the material 204 is extruded from the extruder 202, the tip of the extruder 202 travels relative to the deposition platform 112 in a direction 206.

[00110] In FIG. 2B, an end of a line being deposited is reached. Using a conventional deposition technique, the extruder 202 ceases extruding the material when the end of the line is reached. The extruder 202 is subsequently moved in a direction 208 away from the deposition platform 112. Because of residual pressure, a small quantity of the material 204 may accumulate at the line end causing a blob 210. Thus, use of the conventional deposition technique illustrated in FIG. 2B may result in undesirable line characteristics, such as the blob 210, which can lead to problems with adhesion of subsequent layers and deformation of the physical model.

[00111] FIG. 2C illustrates use of an improved end-of-line deposition technique.

In FIG. 2C, when an end of the line 214 is reached, the tip of the extruder 202 is moved in a direction 212, which is back along the line that was just deposited and away from the deposition platform 112. An extrusion rate of the extruder 202 is reduced when the end of the line 214 is reach, before the end of the line 214 is reached, or concurrently with movement of the tip of the extruder 202 in the direction 212. As the tip of the extruder 202 is moved backward along the line and away from the deposition platform 112, any excess material extruded by the tip of the extruder 202 may be spread more evenly along the end of the line 214, resulting in a line with desirable end-of-line qualities. In particular, the line does not terminate in a blob, such as the blob 210. The improved end- of-line deposition technique illustrated in FIG. 2C may be performed by a 3D printing device, such as the 3D printer device 101 of FIG. 1, based on the end-of-line-technique instructions 149. The tip of the extruder 202 illustrated in FIGS. 2A-2C may correspond to any of the extruder tips 131, 133, 135 of the 3D printer device 101 of FIG. 1.

[00112] FIGS. 3 A and 3B illustrate end-of-line techniques that may be used by a

3D printing device, such as the 3D printer device 101 of FIG. 1. In a particular embodiment, the end-of-line technique illustrated in FIG. 3B may be used by the 3D printer device 101 of FIG. 1 based on the end-of-line techniques instructions 149.

[00113] FIG. 3A illustrates a conventional end-of-line technique. In FIG. 3A, a graph 300 illustrates velocity of a printhead relative to a deposition substrate, such as the deposition platform 112. The graph 300 also indicates an extrusion rate of an extruder of the printhead. The extrusion rate may include a mass flow rate or an end-of-line flow rate. Alternatively, the extrusion rate may correspond to a control parameter that is directly or inversely related to the mass or volumetric flow rate, such as a pressure applied to the extruder, a material feed rate, extruder temperature, and so forth.

[00114] In the example illustrated in FIG. 3A, the graph 300 shows that when the extruder begins to move, the extrusion rate is adjusted to a desired extrusion rate value. Thus, the extrusion rate jumps immediately or nearly immediately to the desired extrusion rate while the extruder gradually accelerates to reach a desired movement rate or velocity. Thus, in the graph 300, there is initially a large gap between the extrusion rate and the velocity of the extruder. The gap reduces as the extruder accelerates, and eventually, the gap remains a relatively constant.

[00115] As a result of the initial gap, a larger quantity of material is deposited at the beginning of the line 304 than at other portions of the line 304, resulting in a blob 306 at the beginning of the line 304. The blob 306 has a blob width 310 that is significantly wider than a target line width 308 of the line 304. The blob 306 results from a difference between the amount of time for the extruder to reach a desired velocity (e.g., an acceleration rate of the extruder) and the amount of time for the extrusion rate to reach a desired extrusion rate. For example, when the extruder is a pasted extruder, pressure applied to a plunger of the extruder results in virtually immediate extrusion at the desired rate. In contrast, inertia and mechanical limitations limit a rate at which the extruder can accelerate.

[00116] FIG. 3B illustrates an improved end-of-line technique in which the extrusion rate is ramped as the velocity of the extruder ramps. For example, as illustrated in a graph 320, the extrusion rate (or a control parameter related to the extrusion rate) may be gradually increased based on the acceleration rate of the extruder. Accordingly, there is no large gap of the beginning of the line between the velocity of the extruder and the extrusion rate.

[00117] A line 324 formed using the end-of-line technique illustrated by the graph

320 is also illustrated in FIG. 3B. The line 324 has a line end 326 having a width approximately the same as the target line width 308. In order to perform the improved end-of-line technique of FIG. 3B, the end-of-line-technique instructions 149 may access the settings 150 to determine information about the acceleration and extrusion rate of a particular printhead. Additionally, although FIGS. 3 A and 3B only illustrate a beginning of a line, similar end-of-line techniques may be performed at a termination point of a line. For example, although FIG. 3B illustrates a relationship between the acceleration rate of an extruder and an extrusion rate of the extruder, a similar relationship occurs when the extruder slows down when the end of a line being deposited is reached. Accordingly, the extrusion rate of the extruder may be gradually decreased as the extruder slows down to avoid forming a blob at the end of the line.

[00118] FIG. 4 illustrates multiple steps associated with generating commands 109, such as G-code instructions, based on a 3D model of an object. In FIG. 4, a 3D model 400 is illustrated as an example of various features disclosed herein. In operation, other 3D models, including 3D models having different shapes, different materials, etc. may be used. The 3D model 400 may include or be based on model data 107 of FIG. 1. In FIG. 4, the 3D model 400 is formed of multiple materials, including the first material 120 and the second material 122. In the example illustrated in FIG. 4, the first material 120 is used as a matrix material, and the second material 122 is used as a filler material.

[00119] After obtaining the 3D model 400 or the model data 107, a slicer application, such as the slicer application 108, may perform slicing operations to generate the commands 109. In the example illustrated in FIG. 4, preliminary slicing is performed to generate a sliced model 402. The sliced model 402 includes multiple slices 404, 406, only two of which are illustrated. Each slice 404, 406 represents a single layer of a physical model based on the 3D model. Each layer of the physical model includes one or more materials. Accordingly, each slice 404, 406 may be divided into regions, with each region corresponding to a particular material. For example, the slice 404 includes a first region corresponding to a portion of the first material 120 and a second region

corresponding to a portion of the second material 122. The slice 406 includes a first region corresponding to a portion of the first material 120 and a second region in which no material is present.

[00120] After the sliced model 402 is generated, the slicer application 108 may modify one or more of the slices based on characteristics of the 3D printer device to be used to print the physical model of the 3D model 400. For example, the slicer application 108 may access the settings 150, the calibration data 148, or both, associated with the 3D printer device 101 of FIG. 1. Alternately, the settings 150, the calibration data 148, or both, may be accessible at the memory 104 of the computing device 102 of FIG. 1.

[00121] In the example illustrated in FIG. 4, the slice 414 is modified relative to the slice 404 of the sliced model 402. For example, in the slice 414, a larger second region associated with the second material has been provided. The second region of the slice 414 may be determined based on dimensions associated with an extruder that deposits the second material. To illustrate, a size of the second region of the slice 414 may be determined based on a size of second extruder tip 133. For example, in order to improve interlayer adhesion and/or printing characteristics, the slicer application 108 may determine that, when the physical model is printed, a portion of the second material 122 will be embedded within the physical model (e.g., entirely enclosed by the first material). Accordingly, the slicer application may determine that an injection technique may be used to deposit at least the embedded portion of the second material. The injection technique may inject the second material into a tunnel formed by void regions in multiple layers of the first material (rather than depositing multiple layers of the second material, with one layer corresponding to one slice of the sliced model 402).

[00122] For example, the slicer application may be configured to generate commands that favor printing one material at a time, and then print with a different material. To illustrate, a first material may be used to form multiple layers corresponding to a set of slices. Even when the slices include regions corresponding to a second material, the slicer application may arrange the commands so that all of the regions that use the first material are printed first. Subsequently, regions that use the second material may be printed, such as by printing on a non-planar surface formed by the first material or by injecting the second material into tunnels or voids defined in the first material. When the first material encloses the second material, the first material may be deposited until just before the access to a region that is ton include the second material is closed off, then the second material may be deposited, as illustrated in FIGS. 10-13.

[00123] As illustrated in FIG. 4, the slicer application may modify some slices to enable using injection techniques. The modified slices may improve printing using injection technique by, for example, widening the area 412 to enable the second extruder tip 133 to fit within the opening correspondent to the area 412.

[00124] Modifying the slices results in a modified sliced model 410, which may be further processed. For example, when a slice, such as the slice 414, includes an enclosed void region 418, the slicer application may process that slice 414 as multiple separate or coupled polygons to limit or reduce starting and stopping a deposition process. During formation of a physical model corresponding to the 3D model 400, the void region 418 may eventually be filled with the second material 122. However, during deposition of the first material 120, the void region 418 remains empty. The slicer application 108 may process the slice 414 to generate multiple polygons, such as a first polygon 420, a second polygon 422, a third polygon 424, and a fourth polygon 426. The multiple polygons 420- 426 may be generated and arranged such that the void region 418 is surrounded by the polygons 420-426, each polygon 420-426 is adjacent to the void region 418, and no polygon 420-426 includes an internal void region. Thus, each polygon 420-426 may be continuous (without spaces, openings, or holes), so that each polygon 420-426 can be printed using continuous lines thereby limiting starting and stopping a corresponding printhead.

[00125] The second slice 406 may also be processed further. For example, the second slice 406 includes multiple regions of the first material 120 and a large gap region in which no material is deposited. In this case, the slicer application 108 may identify and separate the regions to generate separate stacks 430 and 432. Each separate stack 430, 432 may be treated as a separate layer for purposes of generating a tool path. For example, a tool path 434 may be generated for the first stack 430, and a tool path 436 may be generated for the second stack 432. Although not illustrated in FIG. 4, tool paths may also be generated for the polygons 420-426 and other slices of the modified sliced model 410. The tool paths associated with all of the slices and materials together are illustrated in FIG. 4 as a sliced and tool pathed model 440. The sliced and tool pathed model 440 may be processed to generate the commands 109.

[00126] In a particular embodiment, tool paths for multiple slices of the sliced and tool pathed model 440 may be determined such that a continuous line of material extends between multiple layers. For example, as further described in FIG. 5, a tool path for multiple layers of a single material may be generated such that a line of material of a first layer extends a second layer, where the second layer is stacked on the first layer.

[00127] Additionally, in some embodiments, one material may be deposited on a nonplanar surface formed by another material. For example, the slicer application may generate a tool path for depositing the second material that extends across multiple layers of the first material, as illustrated in FIG. 14.

[00128] Further, as described above and with reference to FIGS 10-13, one material may be injection-molded within another material. For example, the sliced and tool pathed model 440 is arranged such that a portion of the second material 122 is injected within cavities defined within the first material 120.

[00129] Thus, FIG. 4 illustrates operations that can be formed by a slicer application, such as the slicer application 108, to improve printer performance, to improve interlayer adhesion, to reduce starting and stopping of printing with a particular printhead (e.g., within a particular layer as well as in between layers). The commands 109 or G-code may be provided to a 3D printing device, such as the 3D printer device 101 of FIG. 1, to generate a physical model of the 3D model 400.

[00130] FIGS. 5-14 illustrate particular aspects of forming a physical object based on a 3D model. In the examples illustrated in FIGS. 5-14, particular aspects of the 3D model 400 is used as examples. For example, the commands 109 may be executed by the 3D printer device of 101 of FIG. 1 to build a physical model of the 3D model 400.

[00131] FIG. 5 illustrates an extruder 502 coupled to a support member 111 and to a drive belt 510. The extruder 502 may include, correspond to, or be included within one of the extruder 130, 132, 134 of FIG. 1. Although the examples illustrated in FIGS. 5-14 include a drive belt 510 coupled to an actuator (not shown), in other examples, the extruder 502 may be coupled to other actuators or devices to move the extruder 502 relative to the deposition platform 112. Alternately, the deposition platform 112 may be moved relative to the extruder 502.

[00132] In the example illustrated in FIG. 5, during a first stage of formation of the physical model, the extruder 502 is moved in a direction 506 to form a portion of a first stack 504. The portion of the first stack 504 may correspond to the first stack 430 of FIG. 4. FIGS. 5-14 are illustrated from a front view, however, as illustrated more clearly by the tool path 434 of the first stack 430 of FIG. 4, the first stack 504 may include multiple lines or rows of material per layer. In FIG. 5, the first stack 504 may be arranged such that a line extends from a first layer onto a second layer, where the second layer is stacked on the first layer. Thus, in FIG. 5, a portion of the extruded material is stacked at 508. Stacking the material, as illustrated at 508, may facilitate interlayered adhesion between layers of the first stack 504.

[00133] FIG. 6 illustrates a second stage during formation of the physical model.

The second stage may be subsequent to the first stage. In FIG. 6, the extruder 502 is moved in a U-turn or curve 512 in order to follow a tool path, such as the tool path 434 illustrated in FIG. 4, to complete the stack 504. The tool path may enable using a single continuous line of extruded material to form multiple rows of material in a layer.

[00134] FIG. 7 illustrates a third stage during formation of the physical model.

The third stage may be subsequent to the second stage. In FIG. 7, the first stack 504 has been completed to a height (i.e., second height 522) determined based on characteristics of the 3D printer device being used. The second height 522 may be selected by the slicer application described with reference to FIG. 4, by the computing device 102, or by the controller 141 of the 3D printer device 101. The second height 522 is less than a distance (e.g., first height 520) between the tip of the extruder 502 and the support member 111 coupled to the extruder 502. For example, the second height 522 may be less than the first height 520 by an amount that is less than a thickness of one layer of the first stack (or by an amount that is less than two layers of the first stack 504) to provide clearance for depositing another stack (such as the second stack 514). Thus, the extruder 502 may be able to deposit a base layer of the second stack 514 on the deposition platform 112 without the first stack 504 coming in contact with the support member 111.

[00135] FIG. 8 illustrates a fourth stage during formation of the physical model.

The fourth stage may be subsequent to the third stage. In FIG. 8, additional components of the 3D printing device are illustrated. For example, members 820 and 822 of a frame are illustrated coupled to the support member 111. An extruder 802 is also illustrated. For example, the extruder 502 may include or correspond to the first printhead 113 (or the first extruder 130), and the extruder 802 may include or correspond to the second printhead 114 (or the second extruder 132) or to the Nth printhead 115 (or the Nth extruder 134).

[00136] In the example illustrated in FIG. 8, the extruder 502 is a filament extruder configured to extrude a filament 810 that is feed to the extruder 502 by drive members 812. A tip of the extruder 502 may be heated to melt the filament 810 for deposition. Further, in the example illustrated in FIG. 8, the extruder 802 is a syringe extruder that includes a plunger 804 coupled to a drive 806. The drive 806 may include a pneumatic drive (e.g., a pressure regulator and/or valve) or a mechanical drive. The drive 806 applies pressure to the plunger 804 to cause a second material 808, to be extruded. The second material may include a paste or a viscous liquid.

[00137] Additionally, the 3D printing device illustrated in FIG. 8 includes multiple cleaning stations, including a first cleaning station 824 and a second cleaning station 826. The 3D printing device in FIG. 8 also includes multiple purging stations, including a first purging station 828 and a second purging station 830. In the example illustrated in FIG. 8, the first stack 504 and the second stack 514 have been printed as described with reference to FIGS. 5-7. Additional layers 814 of the first material have also been deposited, such that an opening 816 is provided in a top portion of a partial physical model 801.

[00138] FIG. 9 illustrates a fifth stage during formation of the physical model. The fifth stage may be subsequent to the fourth stage. FIG. 9 illustrates cleaning the extruder 502. For example, the extruder 502 may be moved to the first cleaning station 824 to clean a tip of the extruder 502, e.g., to remove a clump 832 of the filament 810 that is coupled to a tip of the extruder 502. During cleaning, the first cleaning station 824 may be used to scrape the extruder tip to remove the clump 832.

[00139] In FIG. 9, the extruder 502 may be cleaned based on a determination that a deposition operation associated with the extruder 502 is complete. That is, as many layers of the first material as can be deposited without beginning to close of the opening 816 have been formed. Alternatively, the extruder 502 may be cleaned based on a time associated with forming the partial physical model 801 or on a quantity of material deposited to form the partial physical model 801.

[00140] FIG. 10 illustrates a sixth stage during formation of the physical model.

The sixth stage may be subsequent to the fifth stage, prior to the fifth stage, or concurrent with the fifth stage. In FIG. 10, the extruder 802 may be cleaned, purged, or both. In the arrangement illustrated in FIGS. 8-14, the extruders 502 and 802 cannot be cleaned at the same time; however, in other arrangements, cleansing stations may be arranged to allow cleaning multiple extruders concurrently or simultaneously.

[00141] In a particular example, while the extruder 502 deposits the material to form the partial physical model 801, the second material 808 may sitting unused in the extruder 802. Accordingly, as illustrated in FIG. 10, a portion 834 of the second material 808 may be purged into the second purge station 830 and a tip of the extruder 802 may be cleaned using the second cleaning station 826 before deposition using the second material begins. In other examples, the extruder 802 may be coupled to a mixer, such as the mixer 127, the extruder 802 may be cleaned based on a cure time associated with the mixture. In yet other examples, the extruder 802 may not need to be cleaned after formation of the partial physical model 801 and the sixth stage illustrated in FIG. 10 may be omitted.

[00142] FIG. 11 illustrates a seventh stage during formation of the physical model.

The seventh stage may be subsequent to the fifth stage, subsequent to the sixth stage, or both. In FIG. 11, the extruder 802 is used to deposit a portion of the second material 808 into the opening 816 defined in the first material. The second material 808 may be injected into the opening 816. As illustrated in FIG. 11, the opening 816 is sufficiently wide to accommodate a tip of the extruder 802. In some examples, as illustrated and discussed in FIG. 4, the opening 816 may be adjusted relative to an original 3D model, such as the 3D model 400, in order to accommodate the tip of the extruder 802, as described in the modifying slices step of FIG. 4.

[00143] FIG. 12 illustrates an eighth stage during formation of the physical model.

The eighth stage may be subsequent to the seventh stage. In FIG. 12, the second material 808 has been deposited in the partial physical model 801 to form a partial physical model 803 that includes the partial physical model 801 formed of the first material and filler 844 formed of the second material 808. Additionally, the extruder 802 has been moved to the second cleaning station 826 to be cleaned, purged, or both. For example, after deposition of the filler 844, a clot 842 may be formed at the tip of the extruder 802, which may be cleaned and removed at the second cleaning station 826. As another example, the extruder 802 may be cleaned based on a quantity of the second material 808 deposited to form the filler 844 satisfying a threshold. As another example, the extruder 802 may be cleaned based on a time to deposit the second material 808 satisfying a threshold. As yet another example, the extruder 802 may be cleaned based on a cure time associated with the second material 808. Although not illustrated in FIG. 12, the extruder 802 may also be purged during, before, or after the eighth stage. Similarly, the extruder 502 may be cleaned, purged, or both, during, before, or after the eighth stage.

[00144] FIG. 13 illustrates a ninth stage during formation of the physical model.

The ninth stage may be subsequent to the eighth stage. In FIG. 13, after formation of the partial physical model 803, a portion 850 of the first material 810 may be deposited to cover the filler 844 and to form a partial physical model 805 having non-planar surface 852.

[00145] FIG. 14 illustrates a tenth stage during formation of the physical model.

The tenth stage may be subsequent to the ninth stage. In FIG. 14, a portion 854 of the second material 808 is deposited on the non-planar surface 852. The extruder 802 may follow a curvilinear tool path 856 to deposit the portion 854 on the non-planar surface 852. Deposition of the portion 854 completes formation of a physical model 807 corresponding to the 3D model 400 of FIG. 4.

[00146] FIG. 15 is a flowchart of a particular embodiment of a method 1500 that may be performed by one or more devices or components of the system 100 of FIG. 1. For example, the method 1500 may be performed by the controller 141 of the 3D printer device executing instructions from the memory 142. As another example, the method 1500 may be performed by the processor 103 of the computing device 102 executing instructions from the memory 104.

[00147] The method 1500 includes, at 1502, obtaining model data representing a three-dimensional (3D) model of an object. For example, the processor 103 of FIG. 1 may obtain the model data 107 by reading the model data 107 from the memory 104. As another example, the controller 141 may obtain the model data 107 by receiving the model data 107 via the communication interface 146.

[00148] The method 1500 includes, at 1504, processing the model data to generate a set of commands to direct a 3D printer device to extrude a material to form a physical model associated with the object. The set of commands may be executable to cause an extruder of the 3D printer device to deposit a first portion of the material corresponding to a first portion of the physical model. The set of commands may also be executable to cause the 3D printer device to clean the extruder after depositing the first portion of the material. The set of commands may further be executable to cause the extruder of the 3D printer device to deposit a second portion of the material after cleaning the extruder, where the second portion of the material corresponds to a second portion of the physical model.

[00149] For example, processing the model data may include performing slicing operations, such as operations described with reference to FIG. 4, for generate the commands 109. The set of commands may include machine instruction, such as G-code commands. The set of commands may be generated by the slicer application 108 of the computing device 102. Alternatively, if the 3D printer device 101 includes a slicing application, the set of commands may be generated by the controller 141 or another processor of the 3D printer device 101.

[00150] In some implementations, the method 1500 may also include storing data representing the set of commands, sending data representing the set of commands to the 3D printer via a communication interface, or both. For example, after the commands 109 of FIG. 1 are generated, the commands 109 may be stored at the memory 104 of the computing device 102, sent to the 3D printer device 101, or both.

[00151] In a first implementation, the set of commands is executable to cause the

3D printer device 101 to track a quantity of the material deposited to form the first portion of the physical model. In a second implementation, a slicer application (such as the slicer application 108) generating the set of commands may determine a quantity of the material that will be deposited to form the first portion of the physical model and may include a cleaning sequence in the set of commands based on the quantity of the material deposited satisfying a threshold. In either of these implementations, the set of commands may be executable to cause the 3D printer device 101 to clean the extruder based on the quantity of the material deposited satisfying a threshold. For example, in the first implementation, when one of the material counters 145 indicates that the first extruder 130 has deposits a threshold quantity of the first material 120, the first extruder 130 may be cleaned (e.g., to avoid buildup of material around an opening of the first extruder tip 131). In the second implementation, the set of commands may be arranged sequentially, and the first extruder 130 may be cleaned when the cleaning sequence is reached.

[00152] Alternately, the first implementation, the second implementation, or both, may be based on deposition time rather than quantity of material deposited. To illustrate, in the first implementation, the set of commands is executable to cause the 3D printer device 101 to track a deposition time associated with forming the first portion of the physical model. In a second implementation, a slicer application (such as the slicer application 108) generating the set of commands may determining a deposition time associated with forming the first portion of the physical model and may include a cleaning sequence in the set of commands based on the deposition time satisfying a threshold. In either of these implementations, the set of commands may be executable to cause the 3D printer device 101 to clean the extruder based on the deposition time satisfying a threshold. For example, in the first implementation, when one of the timers 144 indicates that the first extruder 130 has been depositing the first material for a threshold amount of time, the first extruder 130 may be cleaned.

[00153] In yet another implementation, the set of commands is executable, while a particular extruder (e.g., the first extruder 130) is in use, to cause the 3D printer device to track downtime of another extruder (e.g., the second extruder 132 of the Nth extruder 134 or FIG. 1) that is not in use and to clean the particular extruder (e.g., the first extruder 130) based on the downtime of the other extruder (e.g., the second extruder 132 of the Nth extruder 134) satisfying a threshold.

[00154] In some implementations, the set of commands is executable to cause the

3D printer to mix two or more components to form the material. For example, the set of commands may be executable by the 3D printer device 101 to provide the first component 124 (e.g., a resin) and the second component 126 (e.g., a hardening agent) to the mixer 127 to form the mixture 128. In such implementations, the set of commands may cause the 3D printer device to clean the extruder based on the time since mixing satisfying a threshold. For example, the two or more components may begin to cure upon mixing, and the threshold may be based on a cure time of the mixture. In such implementations, the material extruded to form the first portion of the physical model may include or correspond to the mixture.

[00155] Alternatively, in a particular embodiment, the mixture may be used by a second extruder. In this embodiment, the set of commands may be executable to cause the 3D printer device to clean the second extruder after depositing the first portion of the material and before depositing the second portion of the material.

[00156] In some implementations, the set of commands is executable to cause the

3D printer device to deposit a second material after depositing the first portion of the material and before depositing the second portion of the material. The second material may be chemically distinct from the material. For example, the 3D model may include a first model portion representing a matrix material (e.g., a first material) and a second model portion representing a filler material (e.g., a second material). In this example, processing the model data may include identifying a first region of the 3D model that includes the matrix material and a second region of the 3D model that includes the filler material. For some 3D models, at least a portion of the second region may be enveloped by at least a portion of the first region in the 3D model. In this example, the processing the model data may also include automatically modifying the model data to omit at least a portion of the matrix material from the first region of the 3D model. For example, a portion of the matrix material may be omitted to enable a second extruder tip to enter an opening in the matrix material to deposit the filler material. In this example, dimensions of the portion of the matrix material omitted from the first region of the 3D model may be determined based on physical dimensions of the second extruder.

[00157] FIG. 16 is a flowchart of a particular embodiment of a method 1600 that may be performed by one or more devices or components of the system 100 of FIG. 1. For example, the method 1600 may be performed by the controller 141 of the 3D printer device executing instructions from the memory 142. As another example, the method 1600 may be performed by the processor 103 of the computing device 102 executing instructions from the memory 104.

[00158] The method 1600 includes, at 1602, obtaining model data representing a three-dimensional (3D) model of an object. For example, the processor 103 of FIG. 1 may obtain the model data 107 by reading the model data 107 from the memory 104. As another example, the controller 141 may obtain the model data 107 by receiving the model data 107 via the communication interface 146.

[00159] The method 1600 includes, at 1604, processing the model data to generate a set of commands to direct a 3D printer device to extrude one or more materials to form a physical model associated with the object. The set of commands may be executable to cause a first extruder of the 3D printer device to deposit a first portion of a first material corresponding to a first portion of the physical model. The set of commands may also be executable to cause the 3D printer device to clean a second extruder of the 3D printer after depositing the portion of the first material.

[00160] For example, processing the model data may include performing slicing operations, such as operations described with reference to FIG. 4, for generate the commands 109. The set of commands may include machine instruction, such as G-code commands. The set of commands may be generated by the slicer application 108 of the computing device 102. Alternatively, if the 3D printer device 101 includes a slicing application, the set of commands may be generated by the controller 141 or another processor of the 3D printer device 101.

[00161] In some implementations, the method 1600 may also include storing data representing the set of commands, sending data representing the set of commands to the 3D printer via a communication interface, or both. For example, after the commands 109 of FIG. 1 are generated, the commands 109 may be stored at the memory 104 of the computing device 102, sent to the 3D printer device 101, or both.

[00162] In a first implementation, the set of commands is executable to cause the

3D printer device 101 to track a quantity of the first material deposited to form the first portion of the physical model. In a second implementation, a slicer application (such as the slicer application 108) generating the set of commands may determine a quantity of the first material that will be deposited to form the first portion of the physical model and may include a cleaning sequence in the set of commands based on the quantity of the first material deposited satisfying a threshold. In either of these implementations, the set of commands may be executable to cause the 3D printer device 101 to clean the second extruder based on the quantity of the material deposited satisfying a threshold. For example, in the first implementation, when one of the material counters 145 indicates that the first extruder 130 has deposits a threshold quantity of the first material 120, the second extruder 132 may be cleaned. In the second implementation, the set of commands may be arranged sequentially, and the second extruder 132 may be cleaned when the cleaning sequence is reached.

[00163] Alternately, the first implementation, the second implementation, or both, may be based on deposition time rather than quantity of material deposited. To illustrate, in the first implementation, the set of commands is executable to cause the 3D printer device 101 to track a deposition time associated with forming the first portion of the physical model. In a second implementation, a slicer application (such as the slicer application 108) generating the set of commands may determining a deposition time associated with forming the first portion of the physical model and may include a cleaning sequence in the set of commands based on the deposition time satisfying a threshold. In either of these implementations, the set of commands may be executable to cause the 3D printer device 101 to clean the second extruder based on the deposition time of the first extruder satisfying a threshold. For example, in the first implementation, when one of the timers 144 indicates that the first extruder 130 has been depositing the first material for a threshold amount of time, the second extruder 132 may be cleaned.

[00164] In yet another implementation, the set of commands is executable, while the first extruder 130 is in use, to cause the 3D printer device 101 to track downtime of the second extruder 132, which is not in use and to clean the second extruder 132 based on the downtime of the second extruder 132 satisfying a threshold.

[00165] In some implementations, the set of commands is executable to cause the

3D printer device to mix two or more components to form the first material or to form a second material used by the second extruder. For example, the set of commands may be executable by the 3D printer device 101 to provide the first component 124 (e.g., a resin) and the second component 126 (e.g., a hardening agent) to the mixer 127 to form the mixture 128. In such implementations, the set of commands may cause the 3D printer device to clean the second extruder based on the time since mixing satisfying a threshold. In an embodiment, the two or more components may begin to cure upon mixing, and the threshold may be based on a cure time of the mixture. The mixture may be used by a second extruder. In this embodiment, the set of commands may be executable to cause the 3D printer device to clean the second extruder after depositing the first portion of the first material and before depositing a second portion of the first material.

[00166] In some implementations, the set of commands is executable to cause the

3D printer device to deposit a second material after depositing the first portion of the first material and before depositing a second portion of the first material. The second material may be chemically distinct from the first material. For example, the 3D model may include a first model portion representing a matrix material (e.g., a first material) and a second model portion representing a filler material (e.g., a second material). In this example, processing the model data may include identifying a first region of the 3D model that includes the matrix material and a second region of the 3D model that includes the filler material. For some 3D models, at least a portion of the second region may be enveloped by at least a portion of the first region in the 3D model. In this example, the processing the model data may also include automatically modifying the model data to omit at least a portion of the matrix material from the first region of the 3D model. For example, a portion of the matrix material may be omitted to enable a second extruder tip to enter an opening in the matrix material to deposit the filler material. In this example, dimensions of the portion of the matrix material omitted from the first region of the 3D model may be determined based on physical dimensions of the second extruder.

[00167] FIG. 17 is a flowchart of a particular embodiment of a method 1700 that may be performed by one or more devices or components of the system 100 of FIG. 1. For example, the method 1700 may be performed by the 3D printer device 101 executing instructions from the memory 142.

[00168] The method 1700 includes, at 1702, depositing, using a first extruder of a three-dimensional (3D) printer device, a first portion of a first material corresponding to a first portion of a physical model of an object. For example, the 3D printer device 101 of FIG. 1 may use the first extruder 130 to deposit the first material 120 to form a first portion of a physical model of an object (such as the partial physical model 801 of FIG. 8).

[00169] The method 1700 includes, at 1704, cleaning the first extruder after depositing the first portion of the first material. For example, the first extruder 130 may be cleaned at the cleaning station 136 after the first extruder deposits the first material 120 to form a first portion of a physical model of an object. As another example, after the partial physical model 801 is formed as illustrated in FIG. 8, the extruder 502 may be cleaned as illustrated in FIG. 9.

[00170] The method 1700 also includes, at 1706, after cleaning the first extruder, depositing, using the first extruder, a second portion of the first material, the second portion of the first material corresponding to a second portion of the physical model. For example, the first extruder 130 may be may be used to deposit the first material 120 to form a second portion of a physical model of an object after the first extruder 130 is cleaned. As another example, after the first extruder is cleaned, as illustrated in FIG. 9, the first extruder may be used to deposit a second portion of the physical model, as illustrated in FIG. 13.

[00171] In some implementations, the method 1700 may also include storing, at a memory of the 3D printer device, data representing a set of commands to form the physical model, sending data representing the set of commands via a communication interface, or both. For example, after the commands 109 of FIG. 1 are generated, the commands 109 may be stored at the memory 104 of the computing device 102, sent to the 3D printer device 101, or both.

[00172] In a particular embodiment, the method 1700 includes tracking a quantity of the first material deposited to form the first portion of the physical model. In this embodiment, the first extruder may be cleaned based on the quantity of the first material deposited satisfying a threshold.

[00173] In a particular embodiment, the method 1700 includes tracking a deposition time associated with forming the first portion of the physical model. In this embodiment, the first extruder may be cleaned based on the deposition time satisfying a threshold.

[00174] In a particular embodiment, the method 1700 includes tracking downtime of a second extruder of the 3D printer device. In this embodiment, the first extruder may be cleaned based on the downtime of the second extruder satisfying a threshold.

[00175] In a particular embodiment, the method 1700 includes mixing two or more components to form the first material and tracking a time since mixing. In this embodiment, the first extruder may be cleaned based on the time since mixing satisfying a threshold. For example, the two or more components may include a resin and a hardening agent that begin to cure upon mixing. In this example, the threshold may be based on a cure time of a mixture including the two or more components. Mixing the two or more components may include dispensing a resin from a first container of the 3D printer device into a mixer of the 3D printer device and dispensing a hardening agent from a second container of the 3D printer device into the mixer. The resin and the hardening agent may be mixed in the mixer, and the mixer may be in fluid

communication with the first extruder.

[00176] In a particular embodiment, the method 1700 includes mix two or more components to form a second material associated with a second extruder of the 3D printer device and tracking a time since mixing. In this embodiment, the first extruder may be cleaned based on the time since mixing satisfying a threshold. For example, the two or more components may include a resin and a hardening agent that begin to cure upon mixing, and the threshold may be based on a cure time of a mixture. In this example, the method 1700 may include cleaning the second extruder after depositing the first portion of the first material and before depositing the second portion of the first material. [00177] The method 1700 may also or in the alternative include, after depositing the first portion of the first material and before depositing the second portion of the first material depositing a second material using a second extruder of the 3D printer device. The second material may be chemically distinct from the first material.

[00178] FIG. 18 is a flowchart of a particular embodiment of a method 1800 that may be performed by one or more devices or components of the system 100 of FIG. 1. For example, the method 1800 may be performed by the 3D printer device 101 executing instructions from the memory 142.

[00179] The method 1800 includes, at 1802, depositing, using a first extruder of a three-dimensional (3D) printer device, a portion of a first material to form a first portion of a physical model. For example, the 3D printer device 101 of FIG. 1 may use the first extruder 130 to deposit the first material 120 to form a first portion of a physical model of an object (such as the partial physical model 801 of FIG. 8).

[00180] The method 1800 includes, at 1804, after depositing the portion of the first material, cleaning a second extruder of the 3D printer device. For example, after the first extruder 130 is used to deposit the first material 120 to form the first portion of a physical model, the second extruder 132 may be cleaned. As another example, after the extruder 502 is used to form a first portion of a physical model of an object (such as the partial physical model 801 FIG. 8), the extruder 802 may be cleaned, as illustrated in FIG. 10.

[00181] In some implementations, the method 1800 may also include storing, at a memory of the 3D printer device, data representing a set of commands to form the physical model, sending data representing the set of commands via a communication interface, or both. For example, after the commands 109 of FIG. 1 are generated, the commands 109 may be stored at the memory 104 of the computing device 102, sent to the 3D printer device 101, or both.

[00182] In a particular embodiment, the method 1800 includes tracking a quantity of the first material deposited to form the first portion of the physical model. In this embodiment, the second extruder may be cleaned based on the quantity of the first material deposited satisfying a threshold.

[00183] In a particular embodiment, the method 1800 includes tracking a deposition time associated with forming the first portion of the physical model. In this embodiment, the second extruder may be cleaned based on the deposition time satisfying a threshold.

[00184] In a particular embodiment, the method 1800 includes tracking downtime of the second extruder of the 3D printer device. In this embodiment, the second extruder may be cleaned based on the downtime of the second extruder satisfying a threshold.

[00185] In a particular embodiment, the method 1800 includes mixing two or more components to form the first material and tracking a time since mixing. In this embodiment, the first extruder may be cleaned based on the time since mixing satisfying a threshold. For example, the two or more components may include a resin and a hardening agent that begin to cure upon mixing. In this example, the threshold may be based on a cure time of a mixture including the two or more components. Mixing the two or more components may include dispensing a resin from a first container of the 3D printer device into a mixer of the 3D printer device and dispensing a hardening agent from a second container of the 3D printer device into the mixer. The resin and the hardening agent may be mixed in the mixer, and the mixer may be in fluid

communication with the first extruder.

[00186] In a particular embodiment, the method 1800 includes mix two or more components to form the first material and tracking a time since mixing. In this embodiment, the second extruder may be cleaned based on the time since mixing satisfying a threshold. For example, the two or more components may include a resin and a hardening agent that begin to cure upon mixing, and the threshold may be based on a cure time of the mixture. In this example, the method 1800 may include cleaning the second extruder after depositing the first portion of the first material.

[00187] In a particular embodiment, the method 1800 includes mix two or more components to form a second material associated with the second extruder and tracking a time since mixing. In this embodiment, the second extruder may be cleaned based on the time since mixing satisfying a threshold. For example, the two or more components may include a resin and a hardening agent that begin to cure upon mixing, and the threshold may be based on a cure time of the mixture. In this example, the method 1800 may include cleaning the second extruder after depositing the first portion of the first material.

[00188] The method 1800 may also or in the alternative include, after depositing the first portion of the first material and before depositing a second portion of the first material depositing a second material using a second extruder of the 3D printer device. The second material may be chemically distinct from the first material.

[00189] FIG. 19 is a flowchart of a particular embodiment of a method 1900 that may be performed by one or more devices or components of the system 100 of FIG. 1. For example, the method 1900 may be performed by the 3D printer device 101 executing instructions from the memory 142.

[00190] The method 1900 includes, at 1902, moving an extruder of a 3D printer device relative to a deposition platform of the 3D printer device during deposition a material (e.g., a polymer) to form a portion of a first line. For example, one or more of the extruders 130, 132, 134 of FIG. 1 may be moved in the X direction 138, in the Y direction 139, or both, relative to the deposition platform 112. As another example, the extruder 202 of FIG. 2A may be moved in the direction 206 relative to the deposition platform 112 while the material 204 is deposited to form a portion of a line.

[00191] The method 1900 includes, at 1904, after depositing a portion of the material corresponding to a first end of the first line, moving the extruder back along the first line and concurrently moving the extruder away from the deposition platform. For example, after depositing end of a line, one or more of the extruders 130, 132, 134 of FIG. 1 may be moved in the X direction 138, in the Y direction 139, or both, relative to the deposition platform 112 and concurrently moved in the Z direction 140 away from the deposition platform. As another example, the extruder 202 of FIG. 2C may be moved in the direction 212 which is back along the line formed by the material 204 and away from the deposition platform 112. In this context, motion of the extruder relative to the deposition platform 112 may be accomplished by moving the extruder, moving the deposition platform, or both. To illustrate, in FIG. 2C, the extruder 202 may be moved in a direction opposite the direction 206 of FIG. 2A and the deposition platform 112 may be lowered to move away from the extruder 202. Alternatively, one of the extruder 202 or the deposition platform 112 may be stationary while the other is moved.

[00192] The method 1900 may also include reducing an extrusion flow rate of the extruder as the extruder moves away from the deposition platform. For example, when the extruder is a paste extruder or syringe type extruder, pressure applied to a plunger of the extruder may be reduced as the extruder moves away from the deposition platform. As another example, when the extruder is a filament-fed extruder, a feed rate of the filament may be reduced as the extruder moves away from the deposition platform.

[00193] In a particular embodiment, the method 1900 may include forming a physical model by depositing multiple lines of the material including the first line. For example, depositing the multiple lines may include forming a base layer of the material on the deposition platform and stacking multiple layers of the material on the base layer. As another example, depositing the multiple lines may include forming a first stack of multiple layers of the material at a first location relative to the deposition platform and after forming the first stack, forming a second stack of multiple layers of the material at a second location relative to the deposition platform. In this example, the first stack may be formed to a height determined based on a physical configuration of the 3D printer device before the second stack is formed. The physical configuration of the 3D printer device may include or correspond to a distance between an extruder tip of the extruder and a support member coupled to the extruder. To illustrate, in FIGS. 5-7, the first stack 504 is formed by depositing a plurality of lines (arranged as layers) on the deposition platform. After the first stack 504 reaches the second height 522 (which is less that the first height 520), the second stack 514 is formed. In some embodiments, the first line forms at least a portion of a first layer and at least a portion of a second layer, wherein the second layer is stacked on the first layer, as illustrated in FIG. 5.

[00194] In a particular embodiment, the method 1900 may include depositing multiple layers of the material including the first line to form a first portion of a physical model defining a non-planar surface and using a second extruder of the 3D printer device to deposit at least one additional material on the non-planar surface to form a second portion of the physical model. For example, after the extruder 502 is used to deposit a first material to form the non-planer surface 852 of FIG. 14, the extruder 802 may be used to deposit a portion of the second material 808 on the non-planar surface 852.

[00195] FIG. 20 is a flowchart of a particular embodiment of a method 2000 that may be performed by one or more devices or components of the system 100 of FIG. 1. For example, the method 2000 may be performed by the 3D printer device 101 executing instructions from the memory 142.

[00196] The method 2000 includes, at 2002, during extrusion of a material (e.g., a polymer) by an extruder of a three-dimensional (3D) printer device, moving the extruder relative to a deposition platform of the 3D printer device. For example, one or more of the extruders 130, 132, 134 of FIG. 1 may be moved in the X direction 138, in the Y direction 139, or both, relative to the deposition platform 112. As another example, the extruder 202 of FIG. 2 A may be moved in the direction 206 relative to the deposition platform 112 while the material 204 is deposited to form a portion of a line.

[00197] The method 2000 includes, at 2004, during movement of the extruder, adjusting an extrusion rate of the extruder based on an acceleration rate of relative motion of the extruder and the deposition platform. For example, as described with reference to FIG. 3B, the extrusion rate (or an extrusion rate control parameter) may be adjusted based on an acceleration rate of the relative motion of the extruder and the deposition platform to enable formation of line ends (such as the line end 326) without deformations or irregularities, such as blobs.

[00198] In a particular embodiment, the method 2000 may include forming a physical model by depositing multiple lines of the material including the first line. For example, depositing the multiple lines may include forming a base layer of the material on the deposition platform and stacking multiple layers of the material on the base layer. As another example, depositing the multiple lines may include forming a first stack of multiple layers of the material at a first location relative to the deposition platform and after forming the first stack, forming a second stack of multiple layers of the material at a second location relative to the deposition platform. In this example, the first stack may be formed to a height determined based on a physical configuration of the 3D printer device before the second stack is formed. The physical configuration of the 3D printer device may include or correspond to a distance between an extruder tip of the extruder and a support member coupled to the extruder. To illustrate, in FIGS. 5-7, the first stack 504 is formed by depositing a plurality of lines (arranged as layers) on the deposition platform. After the first stack 504 reaches the second height 522 (which is less that the first height 520), the second stack 514 is formed. In some embodiments, the first line forms at least a portion of a first layer and at least a portion of a second layer, wherein the second layer is stacked on the first layer, as illustrated in FIG. 5.

[00199] In a particular embodiment, the method 2000 may include depositing multiple layers of the material including the first line to form a first portion of a physical model defining a non-planar surface and using a second extruder of the 3D printer device to deposit at least one additional material on the non-planar surface to form a second portion of the physical model. For example, after the extruder 502 is used to deposit a first material to form the non-planer surface 852 of FIG. 14, the extruder 802 may be used to deposit a portion of the second material 808 on the non-planar surface 852.

[00200] FIG. 21 is a flowchart of a particular embodiment of a method 2100 that may be performed by one or more devices or components of the system 100 of FIG. 1. For example, the method 2100 may be performed by the controller 141 of the 3D printer device executing instructions from the memory 142. As another example, the method 2100 may be performed by the processor 103 of the computing device 102 executing instructions from the memory 104.

[00201] The method 2100 includes, at 2102, obtaining model data representing a three-dimensional (3D) model of an object. For example, the processor 103 of FIG. 1 may obtain the model data 107 by reading the model data 107 from the memory 104. As another example, the controller 141 may obtain the model data 107 by receiving the model data 107 via the communication interface 146.

[00202] The method 2100 includes, at 2104, processing the model data to generate a set of commands to direct a 3D printer device to extrude a material (e.g., a polymer) to form a physical model associated with the object. The set of commands includes one or more first commands to cause relative motion of an extruder of the 3D printer device and a deposition platform of the 3D printer device during deposition a first portion of the material to form a portion of a first line. The one or more first commands are further executable to, after depositing a second portion of the material corresponding to a first end of the first line, cause relative motion of the extruder and the deposition platform such that the extruder moves back along the first line while the extruder concurrently moves away from the deposition platform. For example, after depositing an end of a line, one or more of the extruders 130, 132, 134 of FIG. 1 may be moved in the X direction 138, in the Y direction 139, or both, relative to the deposition platform 112 and concurrently moved in the Z direction 140 away from the deposition platform. As another example, the extruder 202 of FIG. 2C may be moved in the direction 212 which is back along the line formed by the material 204 and away from the deposition platform 112. In this context, motion of the extruder relative to the deposition platform 112 may be accomplished by moving the extruder, moving the deposition platform, or both. To illustrate, in FIG. 2C, the extruder 202 may be moved in a direction opposite the direction 206 of FIG. 2A and the deposition platform 112 may be lowered to move away from the extruder 202. Alternatively, one of the extruder 202 or the deposition platform 112 may be stationary while the other is moved.

[00203] The set of commands may also include one or more second commands to reduce an extrusion flow rate of the extruder as the extruder moves back along the first line and away from the deposition platform. For example, when the extruder is a paste extruder or syringe type extruder, the one or more second commands may cause pressure applied to a plunger of the extruder to be reduced as the extruder moves away from the deposition platform. As another example, when the extruder is a filament-fed extruder, the one or more second commands may cause a feed rate of the filament to be reduced as the extruder moves away from the deposition platform.

[00204] In a particular embodiment, the set of commands may be executable to cause the 3D printer device to form a physical model by depositing multiple lines of the material including the first line. For example, depositing the multiple lines may include forming a base layer of the material on the deposition platform and stacking multiple layers of the material on the base layer. As another example, depositing the multiple lines may include forming a first stack of multiple layers of the material at a first location relative to the deposition platform and after forming the first stack, forming a second stack of multiple layers of the material at a second location relative to the deposition platform. In this example, the first stack may be formed to a height determined based on a physical configuration of the 3D printer device before the second stack is formed. The physical configuration of the 3D printer device may include or correspond to a distance between an extruder tip of the extruder and a support member coupled to the extruder. To illustrate, in FIGS. 5-7, the first stack 504 is formed by depositing a plurality of lines (arranged as layers) on the deposition platform. After the first stack 504 reaches the second height 522 (which is less that the first height 520), the second stack 514 is formed. In some embodiments, the first line forms at least a portion of a first layer and at least a portion of a second layer, wherein the second layer is stacked on the first layer, as illustrated in FIG. 5.

[00205] In a particular embodiment, the set of commands may be executable to cause the 3D printer device to deposit multiple layers of the material including the first line to form a first portion of a physical model defining a non-planar surface and to cause the 3D printer device to use a second extruder to deposit at least one additional material on the non-planar surface to form a second portion of the physical model. For example, after the extruder 502 is used to deposit a first material to form the non-planer surface 852 of FIG. 14, the extruder 802 may be used to deposit a portion of the second material 808 on the non-planar surface 852.

[00206] In a particular embodiment, the set of commands may be executable to cause the 3D printer device to form the physical model by stacking multiple layers of the material, where the 3D model defines a void region within an area corresponding to at least one layer of the multiple layers. In this embodiment, the set of commands may cause the 3D printer device to form the at least one layer as a set of polygons adjacent to a location corresponding to the void region. For example, the set of polygons may be formed such that no polygon of the set of polygons circumscribes the location

corresponding to the void region. To illustrate, as shown in FIG. 4, when a slicer application identifies the void region 418 within the slice 414, the slicer application may form the set of polygons 420, 422, 424, 426 that circumscribe the void region 418. Thus, the set of commands 109 includes cause a physical model of the slice 414 to be formed by applying lines to form physical models of the polygons 420, 422, 424, 426.

[00207] FIG. 22 is a flowchart of a particular embodiment of a method that may be performed by one or more devices or components of the system 100 of FIG. 1. For example, the method 2200 may be performed by the controller 141 of the 3D printer device executing instructions from the memory 142. As another example, the method 2200 may be performed by the processor 103 of the computing device 102 executing instructions from the memory 104.

[00208] The method 2200 includes, at 2202, obtaining model data representing a three-dimensional (3D) model of an object. For example, the processor 103 of FIG. 1 may obtain the model data 107 by reading the model data 107 from the memory 104. As another example, the controller 141 may obtain the model data 107 by receiving the model data 107 via the communication interface 146.

[00209] The method 2200 includes, at 2204, processing the model data to generate a set of commands to direct a 3D printer device to extrude a material (e.g., a polymer) to form a physical model associated with the object. The set of commands includes one or more first commands to cause relative motion of an extruder of the 3D printer device and a deposition platform of the 3D printer device during deposition of a portion of the material corresponding to a line. The set of commands further includes one or more second commands to adjust an extrusion rate of the extruder based on an acceleration rate of the relative motion. For example, the set of commands may be executable to cause an extrusion rate of one of more of the extruders 130, 132, 134 to be adjusted based on an acceleration rate of the extruder, as described further with reference to FIG. 3B.

[00210] In some implementations, the one or more first commands define a movement rate of the relative motion, such as a movement rate of the extruder. In such implementations, the acceleration rate of the relative motion may be determined based on settings of the 3D printer device. For example, the settings 150 of FIG. 1 may indicate a rate (or a maximum rate) at which the actuators 143 are to change a velocity of the relative motion of the extruders 130, 132, 134 and the deposition platform. Alternately, in such implementations, the acceleration rate of the relative motion may be determined based on a hardware configuration of the 3D printer device. For example, the memory 142 of FIG. 1 may include information indicating a rate (or a maximum rate) at which the actuators 143 are to change a velocity of the relative motion of the extruders 130, 132, 134 and the deposition platform. [00211] In a particular embodiment, the set of commands may be executable to cause the 3D printer device to form a physical model by depositing multiple lines of the material including the first line. For example, depositing the multiple lines may include forming a base layer of the material on the deposition platform and stacking multiple layers of the material on the base layer. As another example, depositing the multiple lines may include forming a first stack of multiple layers of the material at a first location relative to the deposition platform and after forming the first stack, forming a second stack of multiple layers of the material at a second location relative to the deposition platform. In this example, the first stack may be formed to a height determined based on a physical configuration of the 3D printer device before the second stack is formed. The physical configuration of the 3D printer device may include or correspond to a distance between an extruder tip of the extruder and a support member coupled to the extruder. To illustrate, in FIGS. 5-7, the first stack 504 is formed by depositing a plurality of lines (arranged as layers) on the deposition platform. After the first stack 504 reaches the second height 522 (which is less that the first height 520), the second stack 514 is formed. In some embodiments, the first line forms at least a portion of a first layer and at least a portion of a second layer, wherein the second layer is stacked on the first layer, as illustrated in FIG. 5.

[00212] In a particular embodiment, the set of commands may be executable to cause the 3D printer device to deposit multiple layers of the material including the first line to form a first portion of a physical model defining a non-planar surface and to cause the 3D printer device to use a second extruder to deposit at least one additional material on the non-planar surface to form a second portion of the physical model. For example, after the extruder 502 is used to deposit a first material to form the non-planer surface 852 of FIG. 14, the extruder 802 may be used to deposit a portion of the second material 808 on the non-planar surface 852.

[00213] In a particular embodiment, the set of commands may be executable to cause the 3D printer device to form the physical model by stacking multiple layers of the material, where the 3D model defines a void region within an area corresponding to at least one layer of the multiple layers. In this embodiment, the set of commands may cause the 3D printer device to form the at least one layer as a set of polygons adjacent to a location corresponding to the void region. For example, the set of polygons may be formed such that no polygon of the set of polygons circumscribes the location

corresponding to the void region. To illustrate, as shown in FIG. 4, when a slicer application identifies the void region 418 within the slice 414, the slicer application may form the set of polygons 420, 422, 424, 426 that circumscribe the void region 418. Thus, the set of commands 109 includes cause a physical model of the slice 414 to be formed by applying lines to form physical models of the polygons 420, 422, 424, 426.

[00214] FIG. 23 illustrates a block diagram showing data flow among various components of the computing device 102 and the 3D printing device 101. In particular, the block diagram of FIG. 23 illustrates data that is communicated between the 3D modeling application 106, the slicer application 108, the 3D printing device 101, and one or more external devices, such as an external device 2340. In FIG. 23, a 3D modeling application 106 may be used to generate, access, or modify 3D models of one or more objects. For example, the 3D modeling application 106 may be used to obtain first model data corresponding to a first 3D model 2302. The first model data may specify a 3D model of a first object and may indicate a location of the first 3D model 2302 in a model space 2308. The model space 2308 may include a coordinate system and scale information. For example, the model space 2308 may indicate positions relative to an origin point along an X direction or X-axis, a Y direction or Y-axis, and a Z direction or a Z-axis.

[00215] The 3D modeling application 106 may also be used to generate, access, or modify second model data corresponding to a second 3D model 2304. For example, the 3D modeling application 106 may be used to generate the second model data

corresponding to the second 3D model 2304. The second model data may represent a 3D model of a second object. The second model data may also indicate a relative position of the second object or the second 3D model 2304 in the model space 2308. In a particular example, the second object may intersect the first object in the model space 2308. That is, when the second 3D model 2304 is mapped to the model space 2308, and the first 3D model 2302 is mapped to the model space 2308, at least a portion of the second 3D model 2304 may overlap or be embedded within the first 3D model 2302. To illustrate, at least one point of the coordinate system is associated with the first 3D model 2302 and the second 3D model 2304. As another illustration, at least one coordinate of a set of coordinates the first 3D model 2302 overlaps (or is co-located) with at least one coordinate of a set of coordinates of the second 3D model 2304. In some

implementations, the second 3D model may intersect the third 3D model.

[00216] The 3D modeling application 106 may also be used to access, generate, or modify third model data corresponding to a third 3D model 2306. The third 3D model 2306 may represent an electrical interconnect or a set of electrical interconnects. The third 3D model 2306 may also indicate a relative position of the electrical interconnect, the third 3D model 2306, or both, in the model space 2308. In some implementations, at least a portion of the third 3D model 2306 may intersect at least a portion of the first 3D model 2302 in the model space 2308. One or more of the 3D models 2302-2306 may correspond to printable objects, that is, objects that are to be printed by 3D printing device 101.

[00217] Additionally, one or more of the 3D models 2302-2306 may correspond to a non-printing object. For example, in the example illustrated in FIG. 23 and FIG. 24, the second 3D model 2304 corresponds to a non-printing object (e.g., an electrical component) to be inserted in a physical model of an object corresponding to the first 3D model 2302. In this example, the electrical interconnects described by the third 3D model 2306 may provide circuitry or communication paths associated with the electrical component to enable the electrical component and the electrical interconnect to form a functional circuit within the physical object defined by the first 3D model 2302, the second 3D model 2304, and the third 3D model 2306.

[00218] The 3D modeling application 106 may also be used to generate or obtain tags 2310. The tags 2310 may indicate one or more materials to be used to form physical objects corresponding to one or more of the 3D models 2302-2306 or may indicate that one or more of the 3D models 2302-2306 is a non-printing object. The 3D modeling application 106 may use the tags 2310 to generate tagging data 2312, which may be sent to a slicer application 108. For example, when model data 107, corresponding to the 3D models 2302-2306, is provided to the slicer application, the tagging data 2312 may also be provided to the slicer application 108 indicating that the second 3D model 2304 corresponds to a non-printing object.

[00219] Referring to FIG. 24, an example of a process performed by the computing device 102 is illustrated graphically. For example, the first 3D model 2302 of FIG. 23 is illustrated in FIG. 24 as corresponding to a first 3D model of an object formed of a matrix material. Additionally, the second 3D model 2304 of FIG. 23 is illustrated in FIG. 24 as corresponding to an object tagged as a non-printing object, such as an electrical device that has one or more contacts 2402. Further, the third 3D model 2306 of FIG. 23 is illustrated in FIG. 24 as corresponding to as a set of electrical interconnects. The first 3D model, second 3D model, and third 3D model are represented in FIG. 24 as three distinct 3D models, each of which may be defined relative to the model space (e.g., the model space 2308). The first 3D model intersects the second 3D model and the third 3D model in the model space. For example, at least one point of a coordinate system of the model space is associated with the first 3D model 2302 and the second 3D model 2304. To illustrate, at least one coordinate of a set of coordinates the first 3D model 2302 overlaps (or is co-located) with at least one coordinate of a set of coordinates of the second 3D model 2304. In some implementations, the second 3D model may intersect the third 3D model.

[00220] Returning to FIG. 23, after the model data 107 and the tagging data 2312 are obtained by the slicer application 108, the slicer application 108 may process the model data 107 and the tagging data 2312 to generate commands 109 to be provided to the 3D printing device 101. For example, the commands 109 may include G-code, or other information, to direct a 3D printing device 101 regarding steps to perform to generate a physical model corresponding to the model data 107. The model data 107 may include information regarding each of the 3D models 2302-2306, information regarding the model space 2308, other information, such as definitions of materials, etc. In some implementations, the model data 107 may include the tagging data 2312.

[00221] In a particular implementation, the slicer application 108 may form the commands 109 by defining void regions in a matrix material corresponding to the first 3D model 2302 to receive the non-printing object corresponding to the second 3D model 2304 and to receive filler material, such as electrically conductive material corresponding to the third 3D model 2306 of the electrical interconnects. For example, the slicer application 108 may generate a sliced model 2320. The sliced model 2320 may include a plurality of layers 2322 defining or describing material to be deposited by one or more extruders of the 3D printing device 101 in a stacked arrangement in order to form a physical object corresponding to the model data 107. Each of the layers may include the matrix material, the filler material, or both. For example, for some of the layers, the 3D printing device 101 may deposit a first material corresponding to the matrix material to define, for example, a physical support or a structure of a first object corresponding to the first 3D model 2302. For one or more of the layers 2322, the 3D printing device 101 may deposit a second material (e.g., the filler material) corresponding to the third 3D model 2306 to form an electrically conductive trace or region corresponding to an electrical interconnect of the third 3D model 2306. As another example, the 3D printing device 101 may use the matrix material or the filler material, or both to define a void region to receive a physical instance of a second object (e.g., a non-printing object) corresponding to the second 3D model 2304.

[00222] The slicer application 108 may also select from among the layers 2322, one or more layers as an insertion layer 2324 and one or more layers as an interconnect deposition layer 2326. An insertion layer 2324 corresponds to a last printed layer of the matrix material, the filler material, or both, before a non-printing object is inserted in a physical model. For example, an insertion layer 2324 may correspond to a last printed layer to define a void region to receive the non-printing object. The insertion layer 2324 may be selected, such that after the non-printing object is inserted into the physical model, one or more extruders of the 3D printing device 101 can deposit additional material on, over, around, or a combination thereof, the non-printing object without the extruders contacting the non-printing object. For example, the void region may be defined with walls sufficiently high that when the non-printing object is inserted (e.g., recessed) within the physical model, the one or more extruders can pass over the physical instance of the non-printing object without contacting the non-printing object.

[00223] To illustrate, an upper surface of the non-printing object may be below an upper surface of the last printed layer of the physical object, as described further with reference to FIG. 32. The interconnecting deposition layers 2326 may include information indicating when an electrical interconnect material (e.g., the filler material) is to be deposited prior to insertion of a physical instance of a non-printing object. To illustrate, returning to FIG. 24, the non-printing object corresponding to the second 3D model 2304 includes the contacts 2402. In the example illustrated in FIG. 24, one of the contacts 2402 is on the bottom of the non-printing object. To provide sufficient electrical connection between the contact 2402 on the bottom of the non-printing object and an electrical interconnect printed by the 3D printing device, additional material (e.g., electrical interconnect material) may be deposited at a layer lower than a highest most layer printed by the 3D printing device to provide fresh electrical interconnect material just before insertion of the non-printing object. Further, description of the interconnect deposition layer 2326 and insertion layer 2324 is described with reference to FIGS. 29-32 for clarity.

[00224] In a particular embodiment, the slicer application 108 may determine void regions corresponding to the void regions in the first 3D model 2302 corresponding to the second 3D model 2304 and the third 3D model 2306. For example, the void regions may be defined by the matrix material, the filler material, or both in order to allow insertion of a physical instance of a non-printing object corresponding to the second 3D model 2304. Additionally, the void regions may be defined sufficiently to account for 3D printing device characteristics 2314. For example, where an extruder head of the 3D printing device 101 is to deposit material below an uppermost surface (e.g., the highest most layer printed) of previously deposited material, dimensions of the extruder head may be accounted for in determining the void regions to prevent impact of the extruder head with previously printed materials, as described with reference to FIGS. 33 and 34.

[00225] If the slicer application 108 determines that a particular void region is insufficient to allow deposition of a material within a portion of a physical model (e.g., due to depth, width, or other dimensions of the void region, or due to the 3D printing device characteristics 2314), a notification 2334 may be provided to an external device 2340, such as a user interface device. The notification 2334 may indicate a suggestion of manual intervention during formation of the physical model in order to accommodate deposition as needed. For example, the manual intervention may include manually depositing electrical interconnect material prior to inserting a physical instance of a nonprinting object in the partially complete physical model.

[00226] The sliced model 2320 may be used to generate machine instructions 2330.

For example, the slicer application 108 may generate the machine instructions 2330 based on the sliced model 2320. The machine instructions 2330 may include one or more interrupts 2332. For example, an interrupt 2332 may be associated with each insertion layer 2324. When the interrupt 2332 is executed, it may cause a notification to be executed by the 3D printing device 101 or it may cause a notification 2342 to be sent to an external device 2340 (e.g., a pick and place machine, a user interface device, etc.) to indicate that a physical model being generated by the 3D printing device 101 is at a stage to allow insertion of a physical instance of a non-printing object, such as a physical instance of an object corresponding to the second 3D model 2304. Additionally, if a notification 2334 has been provided by the slicer application 108 to the external device 2340 that indicates or suggests manual intervention, an interrupt 2332 may be associated with the manual intervention. The notification 2334 may indicate that a user step is required at the particular stage during formation of the physical object.

[00227] The machine instructions 2330 and interrupts 2332 may be used to perform commands 109 (e.g., G-code provided to the 3D printing device 101) to generate a physical model corresponding to the first 3D model 2302, the third 3D model 2306, and to provide void regions to accommodate a physical instance of a non-printing object corresponding to the second 3D model 2304. The void regions may be shaped such that the second 3D model or a physical instance of a non-printing object corresponding to the second 3D model 2304 can be inserted into a physical model of the first 3D model 2302 from above. For example, a cross- sectional shape of the void region may be determined based on a largest cross-section of the non-printing object. Additionally, where materials are to be deposited below an uppermost surface of previously deposited material by the 3D printing device 101, dimensions of the void regions may need to be determined based on the 3D printing device characteristics 2314.

[00228] Thus, FIG. 23 describes how a slicer application may process multiple models to generate instructions that enable a 3D printing device to deposit materials to form a physical model that includes void regions. The void regions may be configured to receive a physical instance of a non-printing object and a functional circuit may be formed in the physical object.

[00229] FIG. 24, as previously indicated, illustrates a first stage of generation of the sliced model. For example, in FIG. 24, the first 3D model 2302, the second 3D model 2304, and the third 3D model 2306 may be combined to generate a sliced model. In a particular operation, the first model data (e.g., a portion of the model data 107) corresponding to the first 3D model 2302 may be modified to define a void region 2404 corresponding to the second 3D model 2304.

[00230] As previously described, the void region 2404 may have dimensions corresponding to the second 3D model 2304 or may have dimensions larger than the second 3D model 2304. To illustrate, a cross-section of the void region 2404 in a particular plane may have size and shape corresponding to a largest cross-section of the second 3D model 2304. As another example, the dimensions of the void region 2404 may be determined, based at least in part on the 3D printing device characteristics 2314. Additionally, areas to be printed using matrix material may define void regions corresponding to areas to be printed using other materials, such as an electrically conductive material (e.g., interconnect material) corresponding to the third 3D model 2306. Thus, the first model data corresponding to the first 3D model 2302 may be modified to subtract electrical interconnects from matrix material to generate void regions 2406. Thus, an integrated model of the matrix material 2410 may be formed based on the first 3D model 2302, the second 3D model 2304, the third 3D model 2306, as well as characteristics of the 3D printing device 101.

[00231] After the integrated model of the matrix material 2410 is formed, preliminary slicing may be performed to identify insertion layers, interconnect deposition layers, or both. For example, a particular slice of the integrated model of the matrix material 2410 may be identified as an insertion layer 2412. The insertion layer 2412 may correspond to a layer at a top of the void region 2404. That is, the insertion layer 2412 is the last printed layer of the matrix material defining the void region 2404. The preliminary slicing to identify the interconnect deposition layers may determine when material corresponding to electrical interconnects is to be deposited. For example, material corresponding to electrical interconnects 2420 may be deposited during formation or curing of the matrix material within each layer. Alternatively, the matrix material may be printed based on the integrated model of the matrix material 2410 and after multiple layers of matrix material that form at least a portion of one of the void regions 2406 is deposited, electrically conductive material corresponding to the electrical interconnect 2420 may be deposited.

[00232] In a particular example, since the insertion layer 2412 is above an electrical contact corresponding to the bottom contact 2402 of the non-printing object. Sufficient time may have passed after deposition of electrical interconnect material corresponding to the electrical interconnects 2420 that a reliable electrical interconnect may not be formed between the electrical interconnect material and the contact 2402 on the bottom of the electrical component or non-printing object. Accordingly, an interconnect deposition layer may be identified to deposit a portion of electrical interconnect material 2422 after printing the insertion layer 2412, such that the electrical interconnect material 2422 is deposited just before insertion of a physical instance of the second object (e.g., the electrical component) to ensure secure electrical contact between the contact 2402 on the bottom of the electrical component and the electrical

interconnects. Additionally, the electrical interconnects 2424 may be printed after insertion of the non-printing object. Thus, FIG. 24 illustrates formation of a sliced model 2430 and identification of particular layers.

[00233] FIG. 25 illustrates multiple steps associated with generating commands

109, such as G-code instructions, based on a 3D model of an object. In FIG. 25, the 3D model corresponds to the sliced model 2430 of FIG. 24. In operation, other 3D models, including 3D models having different shapes, different materials, etc. may be used. The 3D model may include or be based on the model data 107 of FIG. 1. In FIG. 25, the sliced model 2430 is formed of multiple materials, including the first material 120 and the second material 122. In the example illustrated in FIG. 25, the first material 120 is used as a matrix material, and the second material 122 is used as a filler material. [00234] After obtaining the 3D model or the model data 107, a slicer application, such as the slicer application 108, may perform slicing operations to generate the commands 109. In the example illustrated in FIG. 24, preliminary slicing is performed to generate the sliced model 2430. The sliced model 2430 includes multiple slices 2504, 2506, only two of which are illustrated. Each slice 2504, 2506 represents a single layer of a physical model based on the 3D model. Each layer of the physical model includes one or more materials. Accordingly, each slice 2504, 2506 may be divided into regions, with each region corresponding to a particular material. For example, the slice 2504 includes a first region corresponding to a portion of the first material 120 and a second region corresponding to a portion of the second material 122. The slice 2506 includes a first region corresponding to a portion of the first material 120 and a second region in which no material is present.

[00235] After the sliced model 2430 is generated, the slicer application 108 may modify one or more of the slices based on characteristics (e.g., 3D printing device characteristics) of the 3D printing device 101 to be used to print the physical model. For example, the slicer application 108 may access the settings 150, the calibration data 148, or both, associated with the 3D printing device 101 of FIG. 1. Alternately, the settings 150, the calibration data 148, or both, may be accessible at the memory 104 of the computing device 102 of FIG. 1.

[00236] In the example illustrated in FIG. 25, the slice 2514 is modified relative to the slice 2504 of the sliced model 2430. For example, in the slice 2514, a larger second region associated with the second material has been provided. The second region of the slice 2514 may be determined based on dimensions associated with an extruder that deposits the second material. To illustrate, a size of the second region of the slice 2514 may be determined based on a size of second extruder tip 133. For example, in order to improve interlayer adhesion and/or printing characteristics, the slicer application 108 may determine that, when the physical model is printed, a portion of the second material 122 will be embedded within the physical model (e.g., entirely enclosed by the first material). Accordingly, the slicer application may determine that an injection technique may be used to deposit at least the embedded portion of the second material. The injection technique may inject the second material into a tunnel formed by void regions in multiple layers of the first material (rather than depositing multiple layers of the second material, with one layer corresponding to one slice of the sliced model 2430).

[00237] For example, the slicer application may be configured to generate commands that favor printing one material at a time, and then print with a different material. To illustrate, a first material may be used to form multiple layers corresponding to a set of slices. Even when the slices include regions corresponding to a second material, the slicer application may arrange the commands so that all of the regions that use the first material are printed first. Subsequently, regions that use the second material may be printed, such as by printing on a non-planar surface formed by the first material or by injecting the second material into tunnels or voids defined in the first material. When the first material encloses the second material, the first material may be deposited until just before the access to a region that is ton include the second material is closed off, then the second material may be deposited, as illustrated in FIGS. 31 and 34.

[00238] As illustrated in FIG. 25, the slicer application may modify some slices to enable the layer to be deposited using injection techniques. The modified slices may improve printing using injection techniques by, for example, widening the area 2512 to enable the second extruder tip 133 to fit within the opening correspondent to the area 2512.

[00239] Modifying the slices results in a modified sliced model 2510, which may be further processed. For example, when a slice, such as the slice 2514, includes an enclosed void region 2518, the slicer application may process that slice 2514 as multiple separate or coupled polygons to limit or reduce starting and stopping during a deposition process. During formation of a physical model, the void region 2518 may eventually be filled with the second material 122. However, during deposition of the first material 120, the void region 2518 is empty. The slicer application 108 may process the slice 2514 to generate multiple polygons, such as a first polygon 2520, a second polygon 2522, a third polygon 2524, and a fourth polygon 2526. The multiple polygons 2520-2526 may be generated and arranged such that the void region 2518 is surrounded by the polygons 2520-2526, each polygon 2520-2526 is adjacent to the void region 2518, and no polygon 2520-2526 includes an internal void region. Thus, each polygon 2520-2526 may be continuous (without spaces, openings, or holes), so that each polygon 2520-2526 can be printed using continuous lines, thereby limiting starting and stopping a corresponding printhead.

[00240] The second slice 2506 may also be processed further. For example, the second slice 2506 includes multiple regions of the first material 120 and a large gap region in which no material is deposited. In this case, the slicer application 108 may identify and separate the regions to generate separate stacks 2530 and 2532. Each separate stack 2530, 2532 may be treated as a separate layer for purposes of generating a tool path. For example, a tool path 2534 may be generated for the first stack 2530, and a tool path 2536 may be generated for the second stack 2532. Although not illustrated in FIG. 25, tool paths may also be generated for the polygons 2520-2526 and other slices of the modified sliced model 2510. The tool paths associated with slices and materials together are illustrated in FIG. 25 as a sliced and tool pathed model 2540. The sliced and tool pathed model 2540 may be processed to generate the commands 109.

[00241] In a particular embodiment, tool paths for multiple slices of the sliced and tool pathed model 2540 may be determined such that a continuous line of material extends between multiple layers. For example, as further described in FIG. 26, a tool path for multiple layers of a single material may be generated such that a line of material of a first layer extends to a second layer, where the second layer is stacked on the first layer.

[00242] Additionally, in some embodiments, one material may be deposited on a nonplanar surface formed by another material. For example, the slicer application may generate a tool path for depositing the second material that extends across multiple layers of the first material, as illustrated in FIG. 35.

[00243] Further, as described above and with reference to FIGS. 31-34, one material may be injection-molded within another material. For example, the sliced and tool pathed model 2540 is arranged such that a portion of the second material 122 is injected within cavities defined within the first material 120.

[00244] Thus, FIG. 25 illustrates operations that can be formed by a slicer application, such as the slicer application 108, to improve printing device performance, to improve interlayer adhesion, and to reduce starting and stopping of printing with a particular printhead (e.g., within a particular layer as well as in between layers). The commands 109 (e.g., G-code) may be provided to a 3D printing device, such as the 3D printing device 101 of FIG. 1, to generate a physical model of the sliced and tool pathed model 2540.

[00245] FIGS. 26-35 illustrate particular aspects of forming a physical object based on a 3D model. In the examples illustrated in FIGS. 26-35, particular aspects of the first 3D model 2302, the second 3D model 2304, and the third 3D model 2306 are used as examples. For example, the commands 109 may be executed by the 3D printing device of 101 of FIG. 1 to build a physical model of the sliced and tool pathed model 2540 of FIG. 25. [00246] FIG. 26 illustrates an extruder 2602 coupled to a support member 111 and to a drive belt 2610. The extruder 2602 may include, correspond to, or be included within one of the extruders 130, 132, 134 of FIG. 1. Although the examples illustrated in FIGS. 26-35 include a drive belt 2610 coupled to an actuator (not shown), in other examples, the extruder 2602 may be coupled to other actuators or devices to move the extruder 2602 relative to the deposition platform 112. Alternately, the deposition platform 112 may be moved relative to the extruder 2602.

[00247] In the example illustrated in FIG. 26, during a first stage of formation of the physical model, the extruder 2602 is moved in a direction 2606 to form a portion of a first stack 2604. The portion of the first stack 2604 may correspond to the first stack 2530 of FIG. 25. FIGS. 26-35 are illustrated from a front view, however; as illustrated more clearly by the tool path 2534 of the first stack 2530 of FIG. 25, the first stack 2604 may include multiple lines or rows of material per layer. In FIG. 26, the first stack 2604 may be arranged such that a line extends from a first layer onto a second layer, where the second layer is stacked on the first layer. Thus, in FIG. 26, a portion of the extruded material (e.g., a first material) is stacked, at 2608. Stacking the material, as illustrated at 2608, may facilitate interlay ered adhesion between layers of the first stack 2604.

[00248] FIG. 27 illustrates a second stage during formation of the physical model.

The second stage may be subsequent to the first stage. In FIG. 27, the extruder 2602 is moved in a U-turn or curve 2612 in order to follow a tool path, such as the tool path 2534 illustrated in FIG. 25, to complete the stack 2604. The tool path may enable using a single continuous line of extruded material to form multiple rows of material in a layer.

[00249] FIG. 28 illustrates a third stage of formation of the physical model. The third stage may be subsequent to the second stage. In FIG. 28, the first stack 2604 has been completed to a height (i.e., second height 2622) determined based on characteristics of the 3D printing device being used. The second height 2622 may be selected by the slicer application described with reference to FIG. 25, by the computing device 102, or by the controller 141 of the 3D printing device 101. The second height 2622 is less than a distance (e.g., first height 2620) between the tip of the extruder 2602 and the support member 111 coupled to the extruder 2602. For example, the second height 2622 may be less than the first height 2620 by an amount that is less than a thickness of one layer of the first stack (or by an amount that is less than two layers of the first stack 2604) to provide clearance for depositing another stack (such as the second stack 2614). Thus, the extruder 2602 may be able to deposit a base layer of the second stack 2614 on the deposition platform 112 without the first stack 2604 coming in contact with the support member 111.

[00250] FIG. 29 illustrates a fourth stage during formation of the physical model.

The fourth stage may be subsequent to the third stage. In FIG. 29, layers of the first material (e.g., the matrix material) have been deposited to join the first stack 2604 with the second stack 2614, and electrical interconnects are partially formed from depositing layers of a second material (e.g., filler material) in the first stack 2601 and the second stack 2614. For example, the electrical interconnects 2420 are partially formed into a joined first and second stack 2924. To illustrate, the electrical interconnects 2420 may be formed by an extruder (e.g., a second extruder) depositing a portion of the filler material (e.g., interconnect material).

[00251] FIG. 30 illustrates a fifth stage during formation of the physical model.

The fifth stage may be subsequent to the fourth stage. FIG. 30 illustrates forming a void region for a physical instance of a second object. For example, the first material (e.g., matrix material) and the second material (e.g., the interconnect material) and may be deposited by one or more extruders to form or define the void region 2404. To illustrate, the fifth stage illustrates a formation of sidewalls that define the void region 2404. The sidewalls may be formed from the second material to define the void region, the electrical interconnects 2420, or both.

[00252] FIG. 31 illustrates a sixth stage during formation of the physical model.

The sixth stage may be subsequent to the fifth stage. In FIG. 31, an additional bit of the second material (e.g., the interconnect material) is deposited after the void region 2404 is formed and before insertion of the physical instance of the second object. For example, fresh electrical interconnect material 2422 is deposited in the void region 2404 to electrically couple the physical instance of the second object to the electrical

interconnects 2420. To illustrate, a portion of the electrical interconnect material 2422 is deposited on a portion of the electrical interconnects 2420 which is located on a lower layer than a last printed layer 3102.

[00253] FIG. 32 illustrates a seventh stage during formation of the physical model.

The seventh stage may be subsequent to the fifth stage. In FIG. 32, the physical instance of the second object has been inserted into the void region 2404 and placed in contact with the electrical interconnect material 2422, the contacts 2402, or a combination thereof. The physical instance of the second object may be electrically coupled to the contacts 2402, the electrical interconnects 2420, or both, via the electrical interconnect material 2422.

[00254] FIG. 33 illustrates an eighth stage during formation of the physical model.

The eighth stage may be subsequent to the seventh stage. In FIG. 33, a portion of the first material has been deposited to form a second void region 3306 in the physical model. The second void region may include or correspond to a portion of the void regions 2406. The second void region 3306 may define a shape of the electrical interconnect 2424. In other implementations, the second void region 3304 may define a second shape that is larger than the shape of the electrical interconnect 2424. For example, an extruder may not fit in (extend into) the second void region when the shape is smaller than a cross section of the extruder. As illustrated, in FIG. 33, the second shape of the second void region may be larger (e.g., wider at the top) than the shape of the electrical interconnect 2424 as modeled.

[00255] FIG. 34 illustrates a ninth stage during formation of the physical model.

The ninth stage may be subsequent to the eighth stage. In FIG. 34, after formation of the second void region, a portion of the second material is deposited to form the electrical interconnect 2424. The electrical interconnect 2424 may be electrically coupled to the physical instance of the second object, the electrical interconnects 2420, or a combination thereof. Alternatively, a third material may be deposited to form the electrical interconnect 2426.

[00256] FIG. 35 illustrates a tenth stage during formation of the physical model.

The tenth stage may be subsequent to the ninth stage. In FIG. 35, a portion of the first material is deposited on the electrical interconnect 2424 to form a last layer. Deposition of the portion completes formation of a physical model 3502 corresponding to the sliced and tool pathed model 2540 of FIG. 25.

[00257] FIG. 36 is a flowchart of a particular embodiment of a method 3600 that may be performed by one or more devices or components of the system 100 of FIG. 1. For example, the method 3600 may be performed by the slicer application 108 of FIGS. 1 and 23. As another example, a slicer application of the 3D printing device may perform the method 3600 by executing instructions from the memory 142. As yet another example, the method 3600 may be performed by the processor 103 of the computing device 102 executing instructions from the memory 104.

[00258] The method 3600 includes, at 3602, obtaining first model data specifying a first three-dimensional (3D) model of a first object, the first model data indicating a location of the first 3D model relative to a model space. For example, the slicer application 108 of FIG. 1 may receive or retrieve the model data 107 from the modeling application 106. As another example, the slicer application 108 may obtain the model data 107 by receiving or retrieving the model data 107 via the communication interface 146. As yet another example, the processor 103 of FIG. 1 may obtain the model data 107 by reading the model data 107 from the memory 104. The model data 107 may include or correspond to one or more of the first 3D model 2302, the second 3D model 2304, or the third 3D model 2306 of FIG. 23.

[00259] The method 3600 includes, at 3604, obtaining second model data specifying a second 3D model of a second object, the second model data indicating a location of the second 3D model relative to the model space, where, in the model space, the second 3D model intersects the first 3D model processing. For example, the slicer application 108 of FIG. 23 may receive or retrieve the second model data. In some implementations, the second object may include or correspond to an electrical

component.

[00260] The method 3600 includes, at 3606, processing the first model data and the second model data to generate machine instructions executable by a 3D printing device to generate a physical model of the first object, where the physical model defines a void region to receive a physical instance of the second object. For example, processing the model data may include performing, by the slicer application 108, slicing operations, such as operations described with reference to FIGS. 24 and 25, to generate the commands 109 (e.g., the machine instructions). The void region may include or correspond to the void region 2404 of FIG. 24. The physical model may include or correspond to the physical model 3502 of FIG. 35.

[00261] The machine instructions may include or correspond to the commands 109 of FIGS. 1, 23, and 25, the machine instructions 2330 of FIG. 23, or both. In a particular implementation, the machine instructions 2330 may include the commands 109. In some implementations, the machine instructions may include or correspond to G-code commands. The machine instructions may be generated by the slicer application 108 of the computing device 102. Alternatively, if the 3D printing device 101 includes a slicing application, the machine instructions may be generated by the controller 141 or another processor of the 3D printing device 101.

[00262] The machine instructions may be executable to cause an extruder of the 3D printing device to deposit a first portion of the material corresponding to a first portion of the physical model. The machine instructions may also be executable to cause the 3D printing device to clean the extruder after depositing the first portion of the material. The machine instructions may further be executable to cause the extruder of the 3D printing device to deposit a second portion of the material after cleaning the extruder, where the second portion of the material corresponds to a second portion of the physical model. The machine instructions may further be executable to cause a second extruder to deposit a portion of a second material. In some implementations, the machine instructions do not include instructions or commands to generate a second physical model of the second object.

[00263] In some implementations, the method 3600 may include receiving tagging data indicating that the second object is a non-printing object. For example, the tagging data may include or correspond to the tagging data 2312 of FIG. 23. The method may also include determining dimensions of the void region based on dimensions of the second object and based on the tagging data. In a particular implementation, a cross- sectional shape of the void region is determined based on a cross- sectional shape of the second object.

[00264] In some implementations, the method 3600 may include determining dimensions of the void region based on dimensions of the 3D printing device. In some implementations, the method 3600 may include determining dimensions of the void region to enable the 3D printing device to deposit material on or over the physical instance of the second object without an extruder of the 3D printing device contacting the physical instance of the second object.

[00265] In some implementations, generating the machine instructions may include processing the first model data to generate a sliced model defining a plurality of layers to be deposited to form the physical model of the first object and designating a particular layer of the plurality of layers as an insertion layer. For example, the sliced model may include or correspond to the sliced model 2320 of FIG. 23, and the plurality of layers may include or correspond to the layers 2322 of FIG. 23. Generating the machine instructions may further include including a print interrupt command in the machine instructions such that a printing operation is interrupted after the 3D printing device deposits material corresponding to the insertion layer. For example, the print interrupt command may include or correspond to the interrupts 232 of FIG. 23. In a particular implementation, the print interrupt command, when executed, may cause a notification to be sent to another device, such as a user device.

[00266] In some implementations, the method 3600 may include obtaining third model data specifying a third 3D model of an electrical interconnect. The third model data may indicate a location of the third 3D model relative to the model space, where, in the model space, the third 3D model intersects the first 3D model. The third model data may be processed with the first model data and the second model data to generate the machine instructions. For example, the third 3D model may include or correspond to the third 3D model 2306 of FIG. 23 and may be included in the model data 107 of FIG. 23. In a particular implementation, a first portion of the physical model corresponds to the first 3D model and a second portion of the physical model corresponds to the third 3D model. In some implementations, the machine instructions are executable to cause the 3D printing device to deposit a first material to form the first portion of the physical model and to deposit a second material to form the second portion of the physical model.

[00267] In some implementations, processing the first model data, the second model data, and the third model data may include generating a sliced model associated with the first model data, the sliced model defining a plurality of layers to be deposited to form the first portion of the physical model. Processing the first model data, the second model data, and the third model data may also include determining that dimensions of the void region are insufficient to allow deposition of the second material within a portion of the physical model that corresponds to the void region. Processing the first model data, the second model data, and the third model data may further include generating a notification suggesting manual intervention during formation of the physical model. For example, the notification may include or correspond to the notification 2334 of FIG. 23.

[00268] In some implementations, generating the machine instructions may include processing the first model data to generate a sliced model defining a plurality of layers to be deposited to form the physical model of the first object. Generating the machine instructions may also include designating a particular layer of the plurality of layers as an interconnect deposition layer. For example, the interconnect deposition layer may include or correspond to the interconnect deposition layer 2326 of FIG. 23. Generating the machine instructions may further include including a command in the machine instructions to deposit material corresponding to at least a portion of the electrical interconnect after deposition of material corresponding to the interconnect deposition layer. For example, the electrical interconnect may include or correspond to one or more of the electrical interconnects 2420-2424 of FIG. 24. In a particular implementation, the portion of the electrical interconnect is deposited on a layer lower than the interconnect deposition layer. In some implementations, the machine instructions further include a print interrupt command such that a printing operation is interrupted after the 3D printing device deposits material corresponding to at least a portion of the electrical interconnect.

[00269] In some implementations, the method 3600 may also include storing data representing the machine instructions, sending data representing the machine instructions to the 3D printing device via a communication interface, or both. For example, after the commands 109 of FIG. 1 are generated, the commands 109 may be stored at the memory 104 of the computing device 102, sent to the 3D printing device 101, or both.

[00270] In a first implementation, the machine instructions are executable to cause the 3D printing device 101 to track a quantity of the material deposited to form the first portion of the physical model. In a second implementation, a slicer application (such as the slicer application 108) generating the machine instructions may determine a quantity of the material that will be deposited to form the first portion of the physical model. In some implementations, the machine instructions may include a cleaning sequence based on the quantity of the material deposited satisfying a threshold. In either of these implementations, the machine instructions may be executable to cause the 3D printing device 101 to clean the extruder based on the quantity of the material deposited satisfying a threshold.

[00271] Additionally or alternately, the first implementation, the second implementation, or both, may be based on deposition time. To illustrate, in the first implementation, the machine instructions are executable to cause the 3D printing device 101 to track a deposition time associated with forming the first portion of the physical model. In a second implementation, a slicer application (such as the slicer application 108) generating the machine instructions may determine a deposition time associated with forming the first portion of the physical model. In some implementations, the machine instructions may include a cleaning sequence based on the deposition time satisfying a threshold. In either of these implementations, the machine instructions may be executable to cause the 3D printing device 101 to clean the extruder based on the deposition time satisfying a threshold. In yet another implementation, a cleaning sequence may be further based on downtime of an extruder.

[00272] In some implementations, the machine instructions are executable to cause the 3D printing device to mix two or more components to form the material. For example, the machine instructions may be executable by the 3D printing device 101 to provide the first component 124 (e.g., a resin) and the second component 126 (e.g., a hardening agent) to the mixer 127 to form the mixture 128. In such implementations, the machine instructions may cause the 3D printing device to clean the extruder based on the time since mixing satisfying a threshold. For example, the two or more components may begin to cure upon mixing, and the threshold may be based on a cure time of the mixture. In such implementations, the material extruded to form the first portion of the physical model may include or correspond to the mixture. Alternatively, in a particular embodiment, the mixture may be used by a second extruder.

[00273] In some implementations, the machine instructions are executable to cause the 3D printing device to deposit a second material after depositing the first portion of the material and before depositing the second portion of the material. The second material may be chemically distinct from the material. For example, the physical model may include a first portion representing a matrix material (e.g., a first material) and a second portion representing a filler material (e.g., a second material). The first portion may correspond to the first 3D model 2302, and the second portion may correspond to the third 3D model 2306.

[00274] In a particular implementation, the method 3600 may be performed by a processor and a memory. For example, the processor 103 and the memory 104 of FIG. 1. The memory 104 may be accessible to the processor 103 and the memory 104 may store instructions that when executed cause the processor 103 to perform one or more operations of the method 3600. In some implementations, the memory 104 may include or correspond to a computer-readable storage device.

[00275] As explained above, there are many ways that the slicer application can arrange the pattern of materials to be deposited to form each layer. Characteristics of a 3D print job may vary depending on how the slicer application arranges the pattern lines that make up each of the layers. For example, two different patterns of lines may have different printing characteristics, such as an amount of time used to print the physical model, an amount of material used to print the physical model, etc. As another example, two different patterns of lines may result in physical models that have different characteristics, such as interlayer adhesion, weight, durability, etc. Accordingly, different slicer applications or different settings or configurations of the slicer application can affect the outcome of a particular 3D print job.

[00276] Besides the arrangement of the pattern of materials, other factors can also affect print quality. For example, during extrusion, some materials have a tendency to clog or partially clog a nozzle of the extruder. As the nozzle begins to clog, the flow properties of the nozzle change. To illustrate, a decreased flow area of the nozzle can lead to forming lines that have decreased cross-sectional area, which can reduce print quality. Additionally, if a clog breaks loose during extrusion, the clog can be deposited as a clump or other line deformity. As another example, some materials may aggregate around the nozzle during extrusion to forms clumps that do not occlude the nozzle but can nevertheless lead to problems. These clumps of material can break loose during extrusion to cause clumps or other line deformities in the deposited material.

[00277] Accordingly, one method of improving print quality is to have the slicer application periodically or occasionally interrupt the extrusion process to clean the extruder by inserting cleaning instructions or commands into the machine instructions 2330 or the commands 109. The extruder can be cleaned by moving the extruder to a cleaning station that includes one or more brushes or scrapers. The brushes or scrapers may be passive such that the extruder is moved across the brushes or scrapers to remove excess material. Alternately, the brushes or scrapers may be active (e.g., moving linearly or rotating) to contact the extruder to remove excess material. The cleaning station may also include a waste catcher to catch and retain the removed excess material away from the object being printed. The waste catcher may also be used to purge material from the extruder. For example, material may be purged from the extruder when changing from using a first material to using a second material. As another example, if the material being deposited is reactive (e.g., cures after being mixed or upon exposure to air) some or all of the material may be purged when the extruder is cleaned to avoid curing of the material in the extruder.

[00278] Different types of extruders may be used to deposit different types of materials (e.g., physically or chemically distinct materials). For example, a filament-fed extruder may be used to deposit thermoplastic polymers, such as polylactic acid (PLA), acrylonitrile butadiene styrene (ABS) polymers, and polyamide, among others. Paste extruders, such as pneumatic or syringe extruders, may be used to deposit materials that are flowable at room temperature (or at a temperature controlled by the 3D printing device). Examples of materials that may be deposited using paste extruders include silicone polymers, polyurethane, epoxy polymers. Paste extruders may be especially useful to deposit materials that undergo curing upon exposure to air or when mixed together (such as multi-component epoxies).

[00279] Some 3D printing devices include multiple extruders to improve print speed or to enable printing with multiple different materials. For example, a first extruder may be used to deposit a first material, and a second extruder may be used to deposit second material. In this example, the first and second materials may have different visual, physical, electrical, chemical, mechanical, and/or other properties. To illustrate, the first material may have a first color, and the second material may have a second color. As another illustrative example, the first material may have first chemical characteristics (e.g., may be a thermoplastic polymer), and the second material may have a second chemical characteristics (e.g., may be a thermoset polymer). As yet another illustrative example, the first material may be substantially non-conductive, and the second material may be conductive. In this example, the first material may be used to form a structure or matrix, and the second material may be used to form conductive lines or electrical components (e.g., capacitors, resistors, inductors) of a circuit.

[00280] When a 3D printing device uses multiple extruders to deposit multiple materials, one extruder may be idle (i.e., not extruding material) while another is depositing material. For example, while a first extruder is depositing a matrix material, a second extruder may be idle. Idle extruders may be particularly subject to clogging since flow of material through the extruder may reduce clogging. If the idle extruder becomes clogged, it can lead to reduced print quality as a result of clumps in material that is later deposited by the extruder.

[00281] Accordingly, to improve print quality, a print job may be periodically or occasionally interrupted to clean or purge an idle extruder. To illustrate, after a first extruder deposits a first portion of a first material to form part of a physical object, a second extruder (that was idle while the first extruder deposited the first portion of the first material) may be cleaned. Subsequently, the print job may be resumed. For example, the first extruder may deposit a second portion of the first material to form another part of a physical object. Alternately, the second extruder may deposit a second material, or a third extruder may deposit a third material.

[00282] In some implementations, the first extruder may also be cleaned while the print job is interrupted. For example, cleaning of the first extruder and of the second extruder may be scheduled so that both are cleaned when either one is to be cleaned.

[00283] In some implementations, cleaning operations may be encoded in the G- code or other machine instructions. For example, the slicer application may schedule cleaning operations for one extruder or for multiple extruders. In this example, the G- code or other machine instructions include a sequence of operations associated with printing the physical model (e.g., extrusion operations, extruder movement operations, etc.) and at least one cleaning operation is embedded with the sequence of operations associated with printing the physical model.

[00284] In other implementations, cleaning operations may be scheduled or implemented by the controller of the 3D printing device. For example, the slicer application may provide G-code or other machine instructions that specify a sequence of operations associated with printing the physical model, and, during printing, the controller may interrupt execution of the sequence of operations to perform cleaning operations.

[00285] The cleaning operations may be performed based on an amount of material deposited. For example, the slicer application may determine a quantity of material that will be used to form a portion of the physical model, and the slicer application may insert a cleaning operation into the G-code or machine instructions when the quantity of material that will be used to form the portion satisfies a threshold. Alternately, the controller of the 3D printing device may track the quantity of material that has been deposited and interrupt the 3D printing device to clean one or more extruders when the quantity of material that has been deposited satisfies a threshold. In other

implementations, deposition time of an extruder, idle time of an extruder, or both may be determined or tracked to schedule cleaning operations.

[00286] Some materials begin curing (i.e., solidifying) upon exposure to air or upon mixing. For example, two-part epoxies include an epoxy resin and a hardening agent. After the epoxy resin and the hardening agent are mixed, the mixture begins to cure. When a 3D printing device uses such materials, one or more extruders of the 3D printing device may be cleaned or purged based on a time since mixing the materials (or a time since the materials were exposed to air). For example, if a material that cures after mixing is to be used, the slicer application may generate G-code (or other machine instructions) for mixing the materials. In this example, the slicer application may cause the materials to be mixed based on when the mixture will be needed during printing of the physical model. Additionally, the slicer application may track (e.g., by summing deposition time of all extruders of the 3D printing device) when to schedule a cleaning operation or a purging operation to prevent the mixture from curing in the extruder. In another example, the G-code (or other machine instructions) include instructions for mixing the materials, and the controller of the 3D printing device determines (e.g., based on a timer) when to schedule a cleaning operation or a purging operation to prevent the mixture from curing in the extruder.

[00287] The arrangement of the pattern of materials to be deposited to form each layer may be of particular concern for certain materials. For example, certain materials have a tendency to form blobs or other irregularly shaped deposits (sometimes referred to as "kisses") at the start of a line, the end of a line, or both. A kiss can cause an issue with layer stacking if a portion of the kiss extends above the layer on which it is deposited. A kiss can also, or in the alternative, cause an issue with line arrangement with the layer being printed if the kiss extends beyond the width of its line into an area associated with another line.

[00288] Slicing the 3D model in a manner that reduces line starts and stops can reduce the number of kisses in a physical model. The number of line starts and stops can be reduced by configuring the slicer application to use as few lines as possible (or as few lines as practical in view of other settings or goals) for each layer. For example, when a line extends to an edge of the layer, rather than ending the line, lifting the extruder head and moving to a new location for the next line, the slicer application may instruct the 3D printing device to turn the line (e.g., in a U-turn) to continue the line in another direction.

[00289] The number of line starts and stops can also be reduced by extending lines between layers. For example, when a first layer is complete, rather than ending the line and lifting the extruder head to begin printing the next layer, the line may be extended to overlay a portion of the first layer to immediately begin printing a portion of the second layer. To illustrate, if the first layer is in a horizontal plane, the material forming the line may be deposited to form a vertical or oblique riser up to a plane of the second layer.

[00290] As another example, a first portion of a physical model may be formed by stacking multiple layers of material (e.g., a base layer and one or more additional layers at least partially overlaying the base layer) before moving the extruder head to a different location to form another portion of the base layer. In this example, the multiple layers may be stacked using a single continuous deposition step (e.g., with one start and one stop).

[00291] Another method that may be used to reduce kisses is to perform additional steps at the end of a line. For example, when a line ends, rather than ceasing extruder flow and lifting the extruder head, the extruder head may be caused to move backward (e.g., in a direction back along the line that was just deposited) as the extruder flow is stopped, as the extruder head is lifted, or both. Alternately, the extruder flow can be ceased before the line end is reached. After the extruder reaches the line end, the extruder head can be lifted and moved back along the line. By causing the extruder head to backtrack along the line with flow stopped or as flow stops, potential kiss at the line end can be smoothed out. [00292] Yet another method that may be used to reduce kisses is to control extruder flow in a manner that accounts for acceleration of the extruder head. For example, pressure applied to the material being deposited, temperature of the material, filament feed rate, or a combination thereof, may be used to control a flow rate of material from the extruder. The G-code (or other machine instructions) may include settings for the temperature, the pressure, the filament feed rate, or a combination thereof. Additionally, the G-code (or other machine instructions) may include information indicating a velocity (e.g., speed and direction of travel) for movement of the extruder head during deposition. At the beginning of a line, the extruder head is not able to instantaneously achieve the indicated velocity. Rather, due to inertia and/or settings of the 3D printing device, the extruder head velocity gradually increases to the indicated velocity. During this acceleration from a starting velocity to the indicated velocity, if the same extruder flow rate is used as is used when the extruder is at the indicated velocity, more material will be deposited at the beginning of the line than in the remainder of the line.

[00293] A similar issue arises at the end of the line. That is, when the extruder approaches the end of a line, the extruder is not able to decelerate from the indicated velocity to an ending velocity (e.g., stopped) instantaneously. Rather, the extruder head velocity gradually decreases to the ending velocity. During this deceleration (i.e., negative acceleration), if the same extruder flow rate is used as is used when the extruder is at the indicated velocity, more material will be deposited at the end of the line than in the remainder of the line. Accordingly, kisses or other line irregularities can be reduced by controlling the flow rate of the extruder based on an acceleration rate of the extruder.

[00294] Referring back to FIG. 1, the 3D printing device 101 of FIG. 1 may also include one or more cleaning stations 136, one or more purging stations 137, or both. The cleaning stations 136 may be configured to clean one or more extruder tips, such as the first extruder tip 131, the second extruder tip 133, the Nth extruder tip 135, or a combination thereof. In the examples illustrated herein, each extruder tip 131, 133, 135 may be associated with a corresponding cleaning station, as described further below. However, in other examples, one cleaning station may be used for multiple extruder tips 131, 133, 135. The cleaning station 136 may include a scraper, brushes, or other devices that are used to remove particulate or other foreign matter from the extruder tips 131, 133, 135. In some examples, the cleaning station 136 may be movable relative to the frame 110 or printheads 113-115. For example, the cleaning station 136 may move to the printheads 113-115 to clean the corresponding extruder tip rather than the printheads 113- 115 moving to the cleaning station 136.

[00295] The purging station 137 may be configured to receive a material from one or more of the printheads 113-115 in order to purge an extruder of the printhead 113-115. For example, the mixture 128 may begin to cure upon mixing. Accordingly, the mixture 128, or a portion thereof, may be purged occasionally to avoid curing of the mixture 128 within the extruder 134 or within the mixer 127. As an example, when the Nth extruder 134 is purged, the Nth printhead 115 may be moved adjacent to or over the purge station 137, and at least a portion of the mixture 128 may be extruded by the extruder 134 into the purge station 137. The purge station 137 may be configured to be removable or replaceable such that after the mixture 128 cures in the purge station 137, the cured mixture 128 can be removed without damaging components of the 3D printing device 101. Other materials used by other extruders may be deposited in the purge station 137 occasionally. For example, the second material 122 may include a paste that begins to cure upon exposure to air. In this example, the second extruder 132 may be purged at the purge station 137 occasionally to avoid clogging the second extruder tip 133, the second extruder 132, or both. Further, the first material 120 may include a filament or other thermoplastic polymer, and the first material 120 may be occasionally purged at the purge station 137 in order to retain desirable properties of the filament, to avoid clogging the extruder 130, or both. When a printhead 113-115 is purged at the purge station 137, the printhead 113-115 may also be cleaned at the cleaning station 136 to prepare the printhead 113-115 for use.

[00296] The 3D printing device 101 may also include a memory 142 accessible to the controller 141. The controller 141 may include or have access to one or more timers 144, one or more material counters 145, or both. The material counters 145 may track a quantity of materials in the material containers 119, 121, the component containers 123, 125, a quantity of material in the mixer 127, a quantity of each material deposited to form a physical model of an object, etc. For example, during formation of a first physical model (or a portion of the first physical model), the first material 120 may be deposited by the first printhead 113. During formation of the first physical model, the material counter 145 may track a quantity of the first material 120 that has been deposited. The material counter 145 may also, or in the alternative, track a quantity of material remaining. To illustrate, during formation of the first physical model, while the first material 120 is being deposited, the material counter 145 may track a quantity of the first material 120 that remains in the first material container 119. As another example, when the mixture 128 is deposited to form a portion of the physical model, the material counter 145 may track a quantity of the mixture 128 remaining in the mixer 127. When the quantity of material remaining in the mixer 127 is below a threshold, the controller 141 may cause the mixture 128 to be purged at the purge station 137 and may cause the first component container 123 and the second component container 125 to provide the first component 124 and the second component 126, respectively, to the mixer 127 to generate a new mixture 128. Alternatively, portions of the first component 124 and the second component 126 may be added to an existing mixture 128 in the mixer 127.

[00297] The timers 144 may track an amount of time associated with particular activities of the 3D printing device 101. For example, a first timer of the timers 144 may track a time since mixing the mixture 128. The time since mixing the mixture 128 may be used to determine when to purge the mixture 128. For example, the mixture 128 may be purged before a cure time associated with the mixture 128 is reached. The timers 144 may also, or in the alternatively, track how long a particular printhead 113-115 has been idle. For example, during deposition of the first material 120 to form a portion of a physical model, the second material 122 may sit idle in the second printhead 114 or in the second material container 121. Since the second material 122 may begin to cure upon exposure to air, the portion of the second material 122 exposed at the second extruder tip 133 may begin to cure, potentially causing a clog. Accordingly, based on the timers 144 indicating that the second printhead 114 has been sitting idle for a threshold amount of time, a print activity being performed by the 3D printing device 101 may be interrupted to move the second printhead 114 to the cleaning station 136, the purging station 137, or both, to remove a portion of the second material 122 from the second extruder 132 to avoid clogging the second extruder 132.

[00298] As another example, the timers 144 may indicate how long a particular extruder has been in use. For example, when the first extruder 130 is being used to deposit a portion of material corresponding to a physical object, the first extruder 130 may be cleaned periodically to remove excess material that occasionally aggregates around the first extruder tip 131. Thus, based upon the timers 144, a 3D printing operation being performed by the 3D printing device 101 may be interrupted, and the first extruder 130 may be moved to the cleaning station 136, to the purging station 137, or both, to clean the first extruder tip 131.

[00299] After cleaning of a particular extruder has been performed, the 3D printing operations may resume where they left off. For example, when the first extruder 130 was being used to form a portion of a physical model, and the timer 144 or the material counter 145 indicated cleaning was needed, the print activity may be interrupted, the first extruder 130 may be cleaned, purged or both, and then the printing activity may resume with the first extruder 130 depositing the first material to form a second portion of the physical object. Alternatively, cleaning operations may be scheduled based on the timers

144, the material counter 145, or both, such that the cleaning and/or purging operations occurs between uses of particular extruders. For example, while the first extruder 130 is in use to form a first portion of a physical model, the timers 144, the material counters

145, or both, may reach a value indicating that cleaning is needed. After the first operations being performed by the first extruder 130 is complete (e.g., when an end point associated with the first extruder 130 is reached), the cleaning operation may be performed. The cleaning operation may include cleaning and/or purging the first extruder 130, the second extruder 132, the Nth extruder, or a combination thereof. After the cleaning operation has been performed, printing operations may resume, for example, with the second extruder depositing the second material 122 to form a second portion of the 3D model of the physical object.

[00300] In a particular embodiment, the memory 142 includes cleaning and purging control instructions 147. The cleaning and purging control instructions 147 may include instructions (e.g., a cleaning sequence of instructions, a purging sequence of instructions, or both) that facilitate cleaning and purging of the printheads 113-115. For example, when the controller 141 determines that a cleaning operation is to be performed, the controller 141 may interrupt operations being performed at the 3D printing device 101 and execute the cleaning sequence of instructions of the cleaning and purging control instructions 147. As another example, when the controller 141 determines that a purging operation is to be performed, the controller 141 may interrupt operations being performed at the 3D printing device 101 and execute the purging sequence of instructions of the cleaning and purging control instructions 147.

[00301] In some implementations, the cleaning and purging control instructions

147 may include thresholds associated with the timers 144, thresholds associated with the material counters 145, or both. To illustrate, the thresholds may include a cure time associated with the mixture 128 or a threshold time that precedes the cure time at which the mixture 128 is to be purged and/or cleaned. As another example, the thresholds may include a downtime limit associated with one or more of the printheads 113-115. The downtime limit may be used to determine whether one or more of the printheads 113-115 should be cleaned based on a downtime of the particular printhead. As another example, the thresholds may include use time thresholds associated with the particular printhead 113-115. The use time thresholds may indicate how long a particular printhead 113-115 can be in use before cleaning and/or purging of the particular printhead 113-115 is needed. As another example, the thresholds may include material quantity thresholds that indicate how much material a particular printhead 113-115 can deposit before cleaning and/or purging of the particular printhead 113-115 is needed. In some implementations, the thresholds may be stored as part of the settings 150.

[00302] The cleaning and purging control instructions 147 may also include instructions that cause more than one printhead to be cleaned at a time. For example, when the timers 144 or the material counters 145 indicates that the first printhead 113 is to be cleaned, the cleaning and control instructions 147 may also cause the second printhead 114, the Nth printhead 115, or both, to be cleaned, so that multiple cleaning operations are performed concurrently or sequentially to reduce interruption to print operations.

[00303] The memory 142 may also include calibration data 148. The calibration data 148 may include information that indicates relative positions of the printheads 113- 115. In the particular example illustrated in FIG. 1, the printheads 113-115 may be independently movable by corresponding actuators 143 or may be movable together by one or more actuators 143. The calibration data 148 may indicate distances between printheads 113-115, extruder tips 131, 133, 135, or both. Additionally, or in the alternative, the calibration data 148 may include information about ramp up speeds associated with the actuators 143. For example, the ramp up speeds may indicate how quickly a particular printhead 113-115 can accelerate from stopped to a specified velocity. As another example, the calibration data 148 may include extrusion rates or deposition rates associated with one or more of the printheads 113-115 based on particular control parameters, such as temperature of the extruder or extruder tip, pressure applied to the extruder or extruder tip, a type of material being deposited, a material feed rate, or a combination thereof. For example, the calibration data 148 may include rheology data based on temperature associated with the first material 120, the second material 122, or the mixture 128. As another example, the calibration data 148 may include rheology data associated with the mixture 128 over time.

[00304] The memory 142 may also include test print data 151. The test print data 151 may be used to generate at least a portion of the calibration data 148. For example, the test print data 151 may include commands to generate one or more test print objects using multiple of the printheads 113-115. Positions, orientations, and other information about the test print objects may be measured after a test print is performed and the measurements may be used to adjust the calibration data 148. For example, the 3D printing device 101 may include a measurement device, such as a scanning device (not shown), that automatically measures the test print objects. Alternately, the test print objects may be manually measured and updated calibration data may be provided via a user interface (not shown) or via the computing device 102. The memory 142 may also include end-of-line-technique instructions 149. The end-of-line-technique instructions 149 include instructions that enable formation of line ends having a target width without undesired characteristics, such as bulges and blobs. Thus, the printing device of FIG. 1 may be able to clean extruders based on commands or instructions from a slicer application to increase quality of a print job.

[00305] FIG. 37 illustrates a particular embodiment of a system 3700 that includes a 3D printer device 3701 and a computing device 3702. A communication interface 3746 of the 3D printer device 3701 may be coupled, via a communications bus 3770, to a communication interface 3705 of the computing device 3702. The bus 3770 may include a wired or wireless communications interface. The 3D printer device 3701 is configured to generate physical models of objects based on a 3D model or commands based on model data.

[00306] In a particular embodiment, the computing device 3702 includes a processor 3703 and a memory 3704. The memory 3704 may include a computer readable storage device (e.g., a physical, hardware device, which is not merely a signal), such as a volatile or non-volatile memory device. The computing device 3702 may include a 3D modeling application 3706. The 3D modeling application 3706 may enable generation of 3D models, which can be used to generate model data 3707 descriptive of the 3D models. For example, the 3D modeling application 3706 may include a computer-aided design application.

[00307] The computing device 3702 or the 3D printer device 3701 includes a slicer application 3708. The slicer application 3708 may be configured to process the model data 3707 to generate commands 3709 that the 3D printer device 3701 (or portions thereof) uses during generation of a physical model of an object represented by the model data 3707. In the particular embodiment illustrated in FIG. 37, the commands 3709 may include G-code commands or other machine instructions that are executable by the 3D printer device 3701 (or a portion thereof). The computing device 3702 may also include a communications interface 3705 that may be coupled via the communication bus 3770 to the 3D printer device 3701. For example, the 3D printer device 3701 may be a peripheral device that is coupled via a communication port to the computing device 3702.

[00308] The 3D printer device 3701 includes a frame 3710 and support members

3711 arranged to support various components at the 3D printer device 3701. In particular embodiments, the 3D printer device 3701 may include a deposition platform 3712. In other embodiments, the 3D printer device 3701 does not include a deposition platform

3712 and another substrate or surface may be used for deposition. The 3D printer device 3701 also includes one or more printheads. For example, in the embodiment illustrated in FIG. 37, the 3D printer device 3701 includes a first printhead 3713 and an Nth printhead 3715. Although two particular printheads are illustrated in FIG. 37, in other

embodiments, the 3D printer device 3701 may include more than two printheads or fewer than two printheads. Each printhead 3713, 3715 includes a corresponding extruder with an extruder tip. For example, the first printhead 3713 includes a syringe extruder 3730 having a tip 3731, and the Nth printhead 3715 includes an Nth extruder 3734 including a tip 3735. The Nth extruder 3734 may include another syringe extruder or another type of extruder, such as a filament-fed extruder.

[00309] The controller 3741 may control one or more actuators 3743 to move the deposition platform 3712 relative to the printheads 3713, 3715, to move the printheads 3713, 3715 relative to the deposition platform 3712, or both. For example, in a particular configuration, the deposition platform 3712 may be configured to move in a Z direction 3740. In this example, the printheads 3713, 3715 may be configured to move in an X direction 3738 and a Y direction 3739 relative to the deposition platform 3712. Thus, movement of one or more printheads 3713, 3715 relative to the deposition platform 3712 may involve movement of the deposition platform 3712, movement of one or more of the printheads 3713, 3715, or movement of both the deposition platform 3712 and the printheads 3713, 3715. In other examples, the deposition platform 3712 may be stationary, and one or more of the printheads 3713, 3715 may be moved. In yet other examples, the one or more printheads 3713, 3715 may be stationary, and the deposition platform 3712 may be moved.

[00310] The controller 3741 may also be coupled to a control system associated with the syringe extruder 3730. For example, the syringe extruder 3730 may include a plunger 3732 that is movable to force material through the tip 3731. The plunger 3732 may be pneumatically, hydraulically, or mechanically controlled. For example, in the implementation illustrated in FIG. 37, the plunger 3732 is coupled to a pressurized fluid source 3764 via a pressure regulator 3760 and a valve 3762. In this example, a position of the valve 3762 (e.g., open or closed) is controlled by the controller 3741 to control when the syringe extruder 3730 extrudes material. To illustrate, to begin deposition of the material, the controller 3741 causes the valve 3762 to be moved to an open position, and to stop deposition of the material, the controller 3741 causes the valve 3762 to be moved to a closed position. A pressure setting of the pressure regulator 3760 may be controlled by the controller 3741 to control an extrusion rate (e.g., a material flowrate) of the syringe extruder 3730. To illustrate, to increase the flowrate, the pressure setting of the pressure regulator 3760 may be increased to apply more pressure to the plunger 3732. Conversely, to decrease the flowrate, the pressure setting of the pressure regulator 3760 may be decreased to apply less pressure to the plunger 3732. Although the valve 3762 is illustrated between the pressurized fluid source 3764 and the pressure regulator 3760 in FIG. 37, in other implementations, the pressure regulator 3760 may be positioned between the valve 3762 and the pressurized fluid source 3764.

[00311] The 3D printer device 3701 may also include a memory 3742 accessible to the controller 3741. The memory 3742 may include a computer readable storage device (e.g., a physical, hardware device, which is not merely a signal), such as a volatile or nonvolatile memory device. In a particular embodiment, the memory 3742 includes calibration data 3748. The calibration data 3748 may include information that indicates relative positions of the printheads 3713, 3715. In the particular example illustrated in FIG. 37, the printheads 3713, 3715 may be independently movable by corresponding actuators 3743 or may be movable together by one or more actuators 3743. The calibration data 3748 may indicate distances between printheads 3713-3715, extruder tips 3731, 3735, or both. The calibration data 3748 may include extrusion rates or deposition rates associated with one or more of the printheads 3713, 3715 based on particular control parameters, such as temperature of the extruder or extruder tip, pressure applied to the extruder or extruder tip, a type of material being deposited, a material feed rate, or a combination thereof. For example, the calibration data 3748 may include rheology data based on temperature associated with one or more materials deposited by the extruders 3730, 3734.

[00312] The memory 3742 may also include settings 3750. The settings 3750 may include control parameters or other values used by the controller 3741 to control components of the 3D printer device 3701. For example, the settings 3750 may indicate a value of the pressure setting for the pressure regulator 3760. In other examples, the settings 3750 may indicate a target or actual deposition platform temperature, extruder or extruder tip temperature, filament feed rate, or other information. The settings 3750 may be updated of modified by a user (e.g., via a user interface, not shown), by the computing device 3702 (e.g., via the commands 3709), or via feedback or control input from one or more sensors of the 3D printer device 3701 (such as a temperature sensor 3733 associated with the first printhead 3713).

[00313] In a particular embodiment, the memory 3742 may also include pressure- flowrate data 3752 that indicates a relationship between pressure applied to the plunger 3732 and a flowrate of the syringe extruder 3730. The pressure-flowrate data 3752 may be temperature dependent. To illustrate, the pressure-flowrate data 3752 may specify a first relationship between the pressure and the flowrate associated with first temperature or temperature range, and may specify a second relationship between the pressure and the flowrate associated with second temperature or temperature range. In this embodiment, the controller 3741 may update the settings 3750 occasionally or periodically based on a temperature indicated by the temperature sensor 3733. For example, the pressure setting of the settings 3750 may be updated when the temperature changes from the first temperature to the second temperature.

[00314] The memory 3742 may also include point-deposition technique instructions 3754. The point-deposition technique instruction 3754 include instructions that enable formation features that have a cross-section within a particular layer (or multiple layers) that satisfy a point-deposition criterion (such as being too small to extruder while moving the printheads 3713, 3715 in the X direction 3738, in the Y direction 3739, or both. Examples of point-deposition techniques are described further with reference to FIGS. 42-46. The point-deposition technique instructions 3754 may be applied to commands provided by an external computing device, such as the computing device 3702, in order to improve interlayer adhesion or other properties (e.g., electrical properties) of small, low aspect ratio features within a layer or extending between layers.

[00315] Accordingly, the 3D printer device 3701 enables use of multiple printheads 3713, 3715 with multiple distinct materials. Further, the 3D printer device 3701 includes data, settings and instructions that improve printing using a syringe type extruder, such as the syringe extruder 3730. For example, the pressure-flowrate data 3752 may be used to determine a pressure setting for the pressure regulator 3760 based on, for example, a target line width, a target line height, a temperature associated with the first printhead 3713, other information, or a combination thereof. As another example, the point-deposition technique instruction 3754 may be used to control deposition by the syringe extruder 3730 of material to form small, low aspect ratio features within a layer or extending between layers.

[00316] FIGS. 38A-38B illustrate use pressure (e.g. a pressure setting of the pressure regulator 3760) and velocity (e.g., a rate of motion in the X direction 3738, in the Y direction 3739, in the Z direction 3740, or in a combination thereof, such as during conformal printing with concurrent motion in the X, Y and Z directions 3738-3740) to control line width of material deposited by the syringe extruder 3730 of FIG. 37. In particular, FIG. 38A illustrates line width of a line 3802 deposited at a constant velocity while changing the pressure setting. FIG. 38B illustrates line width of a line 3810 deposited at a constant pressure setting while changing the velocity of motion of the syringe extruder 3730.

[00317] In FIG. 38A, the pressure setting has a first value during a first time 3804 and has a second value during a second time 3806. The second value is greater than the first value; thus, the plunger 3732 of the syringe extruder 3730 is subject to higher pressure during the second time 3806 than during the first time 3804. Due to the pressure difference, the line 3802 has a first line width during the first time 3804 and has a second line width during the second time 3806. The first line width is less than the second line width because, although the velocity of the syringe extruder 3730 is constant, the flowrate of material deposited by the syringe extruder 3730 during the second time 3806 is greater than the flowrate of material during the first time 3804 as a result of the increased pressure. The increased flowrate (with the same extruder velocity) causes the material deposited during the second time 3806 to spread out more than the material deposited during the first time 3804.

[00318] Further, the pressure setting has a third value during a third time 3808.

The third value is less than the first value; thus, the syringe extruder 3730 is subject to less pressure during the third time 3808 than during the first time 3804. Accordingly, during the third time 3808, the line 3802 has a third line width that is less than the first line width. In a particular embodiment, the pressure-flowrate data 3752 may include a table, a set of tables, an algorithm, a set of algorithms, or other information that enables the controller 3741 to determine a value of the pressure setting based on a target line width (e.g., a desired line width at a particular time), a velocity of the syringe extruder 3730, a temperature associated with the syringe extruder 3730, or a combination thereof.

[00319] In FIG. 38B, the pressure is constant; however, the velocity has a first value during a first time 3812 and has a second value during a second time 3814. The second value is less than the first value; thus, the syringe extruder 3730 has a constant flowrate, but a reduced velocity during the second time 3814. Due to the velocity difference, the line 3810 has a first line width during the first time 3812 and has a second line width during the second time 3814. The first line width is less than the second line width. The decreased velocity causes the material deposited during the second time 3814 to spread out more than the material deposited during the first time 3812.

[00320] Further, the velocity has a third value during a third time 3816. The third value is greater than the first value. Accordingly, during the third time 3816, the line 3810 has a third line width that is less than the first line width. In a particular

embodiment, the pressure-flowrate data 3752 may include information that enables the controller 3741 to determine a value of the velocity of the syringe extruder 3730 based on a target line width (e.g., a desired line width at a particular time), a pressure setting of the pressure regulator 3760, a temperature associated with the syringe extruder 3730, or a combination thereof.

[00321] FIGS. 39A-39B illustrate use pressure (e.g. a pressure setting of the pressure regulator 3760) and velocity (e.g., a rate of motion in the X direction 3738, in the Y direction 3739, or a combination thereof) to control line height of material deposited by the syringe extruder 3730 of FIG. 37. In particular, FIG. 39A illustrates line height of a line 3902 deposited at a constant velocity while changing the pressure setting. FIG. 38B illustrates line width of a line 3910 deposited at a constant pressure setting while changing the velocity of motion of the syringe extruder 3730.

[00322] In FIG. 39A, the pressure setting has a first value during a first time 3904 and has a second value during a second time 3906. The second value is greater than the first value; thus, the plunger 3732 of the syringe extruder 3730 is subject to higher pressure during the second time 3906 than during the first time 3904. Due to the pressure difference, the line 3902 has a first line height during the first time 3904 and has a second line height during the second time 3906. The first line height is less than the second line height because, although the velocity of the syringe extruder 3730 is constant, the flowrate of material deposited by the syringe extruder 3730 during the second time 3906 is greater than the flowrate of material during the first time 3904 as a result of the increased pressure. The increased flowrate (with the same extruder velocity) causes the material deposited during the second time 3906 to pile up more than the material deposited during the first time 3904

[00323] Further, the pressure setting has a third value during a third time 3908.

The third value is less than the first value; thus, the syringe extruder 3730 is subject to less pressure during the third time 3908 than during the first time 3904. Accordingly, during the third time 3908, the line 3902 has a third line height that is less than the first line height. In a particular embodiment, the pressure-flowrate data 3752 may include a table, a set of tables, an algorithm, a set of algorithms, or other information that enables the controller 3741 to determine a value of the pressure setting based on a target line height (e.g., a desired line height at a particular time), a velocity of the syringe extruder 3730, a temperature associated with the syringe extruder 3730, or a combination thereof.

[00324] In FIG. 39B, the pressure is constant; however, the velocity has a first value during a first time 3912 and has a second value during a second time 3914. The second value is less than the first value; thus, the syringe extruder 3730 has a constant flowrate, but a reduced velocity during the second time 3914. Due to the velocity difference, the line 3910 has a first line height during the first time 3912 and has a second line height during the second time 3914. The first line height is less than the second line height. The decreased velocity causes the material deposited during the second time 3914 to pile up more than the material deposited during the first time 3912.

[00325] Further, the velocity has a third value during a third time 3916. The third value is greater than the first value. Accordingly, during the third time 3916, the line 3910 has a third line height that is less than the first line height. In a particular embodiment, the pressure-flowrate data 3752 may include information that enables the controller 3741 to determine a value of the velocity of the syringe extruder 3730 based on a target line height (e.g., a desired line height at a particular time), a pressure setting of the pressure regulator 3760, a temperature associated with the syringe extruder 3730, or a combination thereof.

[00326] FIG. 40 illustrates several examples of using pressure, velocity, or both, to control a quantity of material deposited at a particular location (e.g., a line width, a line height, or both). FIG. 40 illustrates the syringe extruder 3730 depositing lines of material within openings 4004, 4014, 4024 formed in another material. For example, the Nth extruder 3734 of FIG. 37 may be used to deposit a matrix material 4002 to form a portion of an object corresponding to a 3D model. The matrix material 4002 may define the openings 4004, 4014, 4024.

[00327] In a first example 4000, the first opening 4004 has a first width. In the first example 4000, the controller 3741 of FIG. 37 may set the pressure setting associated with the pressure regulator 3760 to a first pressure value, and may control the actuators 3743 to achieve movement of the syringe extruder 3730 at a first velocity (e.g., in the X direction 3738, in the Y direction 3739, or a combination thereof). The first pressure value and the first velocity are selected to enable the syringe extruder 3730 to deposit at least a sufficient quantity of material to form a line 4006 that extends to each edge of the opening 4004. For example, the first line 4006 may have a first line width 4008 that is substantially equal to a width of the opening 4004.

[00328] In a second example 4010, the second opening 4014 has a second width.

The second width of the second opening 4014 is greater than the first width of the first opening 4004. To deposit at least a sufficient quantity of material to form a line 4016 that extends to each edge of the opening 4014, the velocity, the flowrate, or both, of the syringe extruder 3730 may be controlled. For example, the controller 3741 of FIG. 37 may set the pressure setting associated with the pressure regulator 3760 to a second pressure value and may control the actuators 3743 to achieve movement of the syringe extruder 3730 at the first velocity. In this example, the second pressure value is greater than the first pressure value used in the first example 4000.

[00329] Alternatively, the controller 3741 of FIG. 37 may set the pressure setting associated with the pressure regulator 3760 to the first pressure value and may control the actuators 3743 to achieve movement of the syringe extruder 3730 at the third velocity. In this example, the third velocity is less than the first velocity used in the first example 4000.

[00330] In a third example 4020, the third opening 4024 has a third width. The third width of the third opening 4024 is less than the first width of the first opening 4004. To deposit at least a sufficient quantity of material to form a line 4026 that extends to each edge of the opening 4024, the velocity, the flowrate, or both, of the syringe extruder 3730 may be controlled. For example, the controller 3741 of FIG. 37 may set the pressure setting associated with the pressure regulator 3760 to a third pressure value and may control the actuators 3743 to achieve movement of the syringe extruder 3730 at the first velocity. In this example, the third pressure value is less than the first pressure value used in the first example 4000.

[00331] Alternatively, the controller 3741 of FIG. 37 may set the pressure setting associated with the pressure regulator 3760 to the first pressure value and may control the actuators 3743 to achieve movement of the syringe extruder 3730 at the second velocity. In this example, the second velocity is less than the first velocity used in the first example 4000.

[00332] Although three examples 4000, 4010, and 4020 are illustrated in FIG. 40, other examples are possible. To illustrate, both the pressure and the velocity may be controlled to achieve a target line width. Further, during formation of a single physical model, different pressure values, different velocities, or both, may be used to achieve different target line widths.

[00333] FIG. 41 illustrates another example of using pressure, velocity, or both, to control a quantity of material deposited at a particular location (e.g., a line width, a line height, or both). FIG. 41 illustrates the syringe extruder 3730 depositing lines of material within an opening 4100 formed in another material. For example, the Nth extruder 3734 of FIG. 37 may be used to deposit the matrix material 4002 to form a portion of an object corresponding to a 3D model. The matrix material 4002 may define the opening 4100 (only a portion of which is illustrated in FIG. 41).

[00334] The tip of the syringe extruder 3730 had an orifice through which material is extruded. The orifice has a first dimension (e.g., an inner diameter) that is different from a second dimension (e.g., an outer diameter) of an outer surface of the tip of the syringe extruder 3730. Further, in some embodiments, the tip of the syringe extruder 3730 is tapered (as illustrated in FIG. 41). Accordingly, the tip of the syringe extruder 3730 may be positioned at an offset distance 4104 from a wall of the opening 4100 when the syringe extruder 3730 is depositing material. Depositing material at the offset distance 4104 from the wall of the opening 4100 may lead to issues with the physical model. For example, if a line 4108 deposited closest to the wall does not contact the wall, the physical model material deposited by the syringe extruder 3730 may not adhere sufficiently to the material 4002.

[00335] In the example illustrated in FIG. 41, the line 4108 deposited closest to the wall has a first line width 4106, and other lines 4112 deposited further from the wall have a second line width 4110. The first line width 4106 and the second line width are controlled based on pressure applied to the plunger 3732 of the syringe extruder 3730, velocity of motion of the syringe extruder 3730, or both. For example, when forming the line 4108 closest to the wall a higher value of the pressure setting may be used than when forming the other lines 4112. Alternatively, or in addition, when forming the line 4108 closest to the wall a lower velocity of motion of the syringe extruder 3730 may be used than when forming the other lines 4112. Thus, different pressure settings may be used to form a single physical model or portions of a single layer of the single physical model.

[00336] FIGS. 42-46 illustrate several aspects of forming a physical model of an object corresponding to a 3D model using a syringe extruder. Each of FIGS. 42-46 includes a perspective view and a front view.

[00337] FIG. 42 illustrates 3D model 4202 of an object. For example, the 3D model 4202 may be represented by the model data 3707 of FIG. 37. In this example, the 3D model 4202 may include one or more solid body models formed using a 3D computer-aided design (CAD) application, such as the 3D modeling application 3706 of FIG. 37. The 3D model includes a first portion (a body 4204) corresponding to a first material and a second portion (e.g., a feature 4206) corresponding to a second material. For example the body 4204 may correspond to a matrix material (e.g., a non-conductive structural polymer), and the feature 4206 may correspond to a filler material (e.g., a conductive polymer forming at least part of an electrical interconnect).

[00338] FIG. 43 illustrates a sliced model 4302 formed based on the 3D model

4202. For example, the sliced model 4302 may include a plurality of slices 4308. The sliced model 4302 may be formed by the slicer application 3708 based on the model data 3707 representing the 3D model 4202.

[00339] In FIG. 43, each slice corresponds to a layer to be printed by a 3D printing device (such as the 3D printer device 3701 of FIG. 37) to form a physical model of the object. Each of the slices may include one or more regions, with each region

corresponding to a single material. For example, a first slice 4310 (e.g., the bottom slice in FIG. 43) may include only a single region, indicating that a layer corresponding to the first slice 4310 is to be printed entirely of a first material. However, a second slice 4312 (e.g., a top slice in FIG. 43) may include two regions, i.e., a first region 4304

corresponding to the first material and a second region 4314 corresponding to a second material. Thus, printing the second slice 4312 includes depositing a portion of the first material to form the first region 4304 and depositing a portion of the second material to form the second region 4314.

[00340] The second region 4312 is a portion of a feature (e.g., the electrical interconnect described with reference to FIG. 42) that extends through multiple slices of the sliced model 4302 (and accordingly, when formed will extend through multiple layers of the physical model of the object). The slicer application 3708 may analyze the feature to determine whether the feature satisfies a point-deposition criterion. For example, if the feature has a cross-sectional dimension (e.g., a length, a width, a diameter, an aspect ratio, or a combination thereof) within one or more slices, the feature may satisfy the point- deposition criterion. To illustrate, the point-deposition criterion may be satisfied if the feature has an aspect ratio that is less than an aspect ratio threshold, has a diameter (or length) that is less than a length threshold, has a cross-sectional area that is less than a cross-sectional area threshold, or has a combination thereof (e.g., has an aspect ratio that is less than an aspect ratio threshold and has a cross-sectional area that is less than a cross-sectional area threshold). The point-deposition criterion may be determined based on characteristics of the 3D printing device that will be used to form a physical model of the sliced model 4302. For example, for a particular 3D printing device, such as the 3D printer device 3701 of FIG. 37, thresholds for the point-deposition criterion may be selected based on a minimum reliable line length of the 3D printer device 3701. The minimum reliable line length refers to a length of a smallest length of a line that can be deposited by the 3D printing device while maintaining desired characteristics, such as interlayer adhesion, electrical characteristics (e.g., if the material being deposited in conductive), etc.

[00341] For example, a first part of the feature may extend along a single slice and may have a first interlayer feature dimension 4320. In this example, a second part of the feature may extend more or less vertically through several slices and may have a second interlayer feature dimension 4322. The first interlayer feature dimension 4320 may not satisfy the point-deposition criterion since the first part has a large aspect ratio and a large length within the single slice. However, the second interlayer feature dimension 4322 may satisfy the point-deposition criterion in multiple slices since the second part has a small aspect ratio and a small length in each of the multiple slices.

[00342] FIG. 44 illustrates a modified sliced model 4402 based on the sliced model

4302 of FIG. 43. The modified sliced model 4402 may include one or more modified slices 4404, which are modified relative to slices of the sliced model 4302. In the example illustrated in FIG. 44, the modified slices 4404 are modified to enable forming the second region 4312 of FIG. 43 according to a point deposition techniques.

[00343] For example, the tip 3731 of the syringe extruder 3730 may have a tapering shape, as illustrated in FIG. 44. The second region 4312 of the feature that extends through multiple slices in the sliced model 4302 of FIG. 43 has a shape 4406 illustrated in FIG. 44. The shape 4406 of the second region 4312 satisfies the point- deposition criterion in each slice that is modified in FIG. 44. For example, the shape 4406 is only slightly larger than an outer dimension of the tip 3731 of the syringe extruder.

[00344] In the example of FIG. 44, multiple slices have been modified to accommodate the tip 3731. For example, in the top seven slices of FIG. 44, the shape 4406 has been modified to provide an opening sufficiently large for the tip 3731 to extend within layers corresponding to the slices (as illustrated in FIG. 45). Thus, the modified slices 4404 enable use of a point deposition technique in which the tip 3731 is positioned below an upper surface of a physical model, and the tip 3731 is used to extrude material while moving vertically (e.g., in a Z direction 3740, as illustrated in FIGS. 45 and 46) rather than laterally (e.g. in the X direction 3738, the Y direction 3739, or both).

[00345] FIG. 45 illustrates a first stage during formation of a physical model 4502 corresponding to the modified sliced model 4402. For example, a plurality of layers 4508 of a first material 4504 have been deposited leaving an opening 4510 in each layer that corresponds to one of the modified slices 4404. The opening 4510 in each layer is to accommodate the tip 3731 and to receive a second material 4506 deposited according to a point-deposition technique. In FIG. 45, the tip 3731 is moved vertically (e.g., in the Z direction) to insert the tip 3731 into openings 4510 within layers of the first material 4504.

[00346] FIG. 46 illustrates a second stage during formation of the physical model

4502 corresponding to the modified sliced model 4402. The second stage may be subsequent to the first stage illustrated in FIG. 45. In the second stage, the tip 3731 is moved vertically (e.g., in the Z direction) while depositing the second material 4506 to fill the opening in the layers of the first material.

[00347] For example, as illustrated in the callout of the perspective view, the layers

4508 may include a first layer 4602 and a second layer 4604. The second layer 4604 may be positioned above and in contact with the first layer 4602. The first layer 4602 includes a first region 4610 corresponding to a portion of the first material 4504 and a second region 4612 corresponding to a portion of the second material 4506. The second layer 4604 includes a third region 4620 corresponding to a portion of the first material 4504 and a fourth region 4622 corresponding to a portion of the second material 4506. In the example illustrated in FIG. 46, multiple layers of the first material 4504 are deposited before the second material 4506 is deposited. To illustrate, the first region 4610 and the third region 4620 may be formed before the second region 4612 and the fourth region 4622 are formed.

[00348] The openings in the layers of the first material 4504 to accommodate the tip 3731 for a tapered shape. Accordingly, a quantity of the second material 4506 deposited in adjacent layers (such as the first layer 4602 and the second layer 4604) may be different. To illustrate, as the tip 3731 moves in the Z direction, the tip 3731 deposits more of the second material 4506 in each layer than in a previous layer. Pressure applied to a plunger of the syringe extruder or velocity of motion of the tip 3731 may be used to vary the quantity of the second material deposited in each layer. For example, as the tip 3731 is moved in the Z direction, the pressure setting of the pressure regulator 3760 may remain constant and the rate of motion in the Z direction may change (e.g., decrease) over time. As another example, as the tip 3731 is moved in the Z direction, the pressure setting of the pressure regulator 3760 may be changed (e.g., increased) and the rate of motion in the Z direction may remain constant. As yet another example, as the tip 3731 is moved in the Z direction, the pressure setting of the pressure regulator 3760 may be changed (e.g., increased) and the rate of motion in the Z direction may be changed.

[00349] FIG. 47 is a flowchart of a particular embodiment of a method 4700 that may be performed by one or more devices or components of the system 3700 of FIG. 37. For example, the method 4700 may be performed by the controller 3741 of the 3D printer device 3701 executing instructions from the memory 3742. As another example, the method 4700 may be performed by the processor 3703 of the computing device 3702 executing instructions from the memory 3704.

[00350] The method 4700 includes, at 4702, obtaining model data specifying a three-dimensional (3D) model of an object. The 3D model includes a first portion corresponding to a first material and a second portion corresponding to a second material. For example, the 3D model may correspond to the model data 3707 of FIG. 37. As another example, the 3D model may include or correspond to the 3D model 4202 of and the feature corresponding to the second portion may correspond to the feature 4206. In some implementations, the first material may include a matrix material (e.g., a non- conductive material, such as a polymer), and the second material may include a filler material (e.g., a conductive material, such as a conductive polymer). Thus, the 3D model may include a conductive features, such as a wire, formed of the second material extending though portions of the first material.

[00351] The method 4700 includes, at 4704, processing the model data to generate a sliced model defining a plurality of layers to be deposited to form a physical model of the object. For example, the sliced model may include or correspond to the sliced model 4302 of FIG 43. In this example, the sliced model may include a plurality of slices 4308.

[00352] The method 4700 includes, at 4706, identifying, based on the sliced model, an elongated feature extending between multiple layers of the plurality of layers and having, in each of the multiple layers, cross-sectional dimensions that satisfy a point- deposition criterion. For example, the elongated feature may correspond to or include the feature 4306 that has the second intralayer feature dimension 4322. In some

implementations, the point-deposition criterion is satisfied when an aspect ratio determined based on the cross-sectional dimensions is less than an aspect ratio threshold.

[00353] In some implementations, after identifying the elongated feature, the sliced model may be modified. For example, the slice model may be modified to increase a cross-sectional area of the elongated feature in at least one layer of the multiple layers. To illustrate, the cross-sectional area of the elongated feature may be increased based on a dimension associated with an extruder of the 3D printing device, where the extruder is associated with the second material. For example, in the sliced model 4302 of FIG. 43, the feature 4306 has a first cross-section, which is modified to generate the modified sliced model 4402 of FIG. 44. The modified sliced model 4402 is used to form the layers 4508 of FIG. 45, which include openings to receive a portion of the second material to form a physical model of the elongated features. In this example, the cross-section of the elongated feature in the first layer of the physical model 4502 corresponds to a cross- section of the opening in the first layer. Also, the cross-sectional area of the feature 4206 in the 3D model 4202 is less than a cross- sectional area of the opening 4510 in the at least some of the layers 4508. Thus, in some layers, the sliced model 4302 is modified to increase a cross-sectional dimension associated with the feature.

[00354] The method 4700 includes, at 4708, generating machine instructions executable by a 3D printing device to, for a first layer of the multiple layers, deposit a portion of the first material to define an opening associated with the elongated feature and deposit a portion of the second material within the opening according to a point- deposition technique. The machine instructions may include or correspond to the commands 3709 of FIG. 37. The machine instructions may enable depositing a portion of the first material (e.g., corresponding to the first region 4304 of FIG. 43) to define an opening corresponding the opening 4408 of FIG. 44. The machine instructions may also enable depositing a portion of the second material within the opening as illustrated in FIG. 46. [00355] In some implementations, the machine instructions include instructions to translate a first extruder associated with the first material along a first axis, along a second axis, or both, to deposit the portion of the first material. For example, the machine instruction may cause the one or more of the extruders 3730, 3734 of FIG. 37 to move in the X direction 3738, in the Y direction 3739, or both, while depositing the first material. In some such implementations, the portion of the second material is deposited according to a point-deposition technique without translating a second extruder along the first axis and without translating the second extruder along the second axis. To illustrate, the syringe extruder 3730 may deposit the second material according to the point-deposition technique by extruding the second material while stationary in the X direction 3738 and in the Y direction 3739; however, the syringe extruder 3730 may move relative to the deposition platform 3712 in the Z direction 3740.

[00356] In some implementations, the point-deposition technique causes a quantity of the second material sufficient to fill the opening to be deposited. The quantity of the second material deposited may be determined based on a flowrate of the second material. To illustrate, the second material may dep be deposited using the syringe extruder 3730. In this illustrative example, generating the machine instructions may include determining a pressure setting and an extrusion time (or values of others of the settings 3750) to cause the syringe extruder 3730 to deposit the quantity of the second material. For example, as illustrated in FIG. 46, the pressure setting, the velocity of motion of the tip 3731 of the syringe extruder 3730, or both, may be controlled to substantially fill the opening 4510 of FIG. 45 with the second material 4506.

[00357] In a particular implementation, the machine instructions may cause the 3D printing device to deposit at least a second layer of the multiple layers before depositing the portion of the second material within the opening. To illustrate, in FIG. 45, regions 4610 and 4620 of the first and second layers 4602 and 4604, respectively, are formed of the first material 4504 before the second material 4506 is deposited in an opening 4510 formed in the first and second layers 4602 and 4604. Thus, the opening 4510 extends between multiple layers, including the first layer and the second layer. The syringe extruder 3730 is used to deposit a portion of the second material 4506 in the opening 4510 sufficient to fill the opening 4510. For example, as illustrated in FIGS. 45 and 46, the machine instructions may cause the tip 3731 of the syringe extruder 3730 to be positioned below a surface of the layers of the first material 4504 during at least a portion of the point-deposition technique. In this example, the tip 3731 of the syringe extruder 3730 may be translated in a direction perpendicular to a surface of the layers of the first material 4504 (e.g., in the Z direction) during at least a portion of the point-deposition technique.

[00358] FIG. 48 is a flowchart of a particular embodiment of a method 4800 that may be performed by one or more devices or components of the system 3700 of FIG. 37. For example, the method 4800 may be performed by the 3D printer device 3701 (or a one or more components thereof).

[00359] The method 4800 includes, at 4802, receiving machine instructions that enable generating a physical model of an object including an elongated feature. The elongated feature extends between multiple layers of a plurality of layers of the physical model and has, in each of the multiple layers, a cross-sectional dimension that satisfies a point-deposition criterion. For example, the object may correspond to the sliced model 4302 of FIG. 43, which includes the feature 4306, a portion of which extends through multiple slices of the sliced model 4302.

[00360] The method 4800 includes, at 4804, depositing, using a first extruder of a three-dimensional (3D) printer device, a portion of a first material to define an opening associated with the elongated feature of the physical model. For example, the 3D printer device 3701 of FIG. 37 may be used to deposit a portion of the first material 4504 of FIG. 45 in a manner that defines the opening 4510 associate with at least a portion of the feature 4306.

[00361] The method 4800 includes, at 4806, depositing, using a second extruder of the 3D printer device, a portion of a second material to form a portion of the elongated feature according to a point-deposition technique. The point-deposition technique causes the portion of the second material to be deposited within the opening. For example, the tip 3731 of the syringe extruder 3730 may be inserted into at least a portion of the opening 4510 in the first material 4504 of FIG. 45. In this example, the syringe extruder 3730 may deposit a portion of the second material 4506 in the opening as the syringe extruder 3730 is moved in the Z direction (as illustrated in FIG. 46).

[00362] FIG. 49 is a flowchart of a particular embodiment of a method 4900 that may be performed by one or more devices or components of the system 3700 of FIG. 37. For example, the method 4900 may be performed by the controller 3741 of the 3D printer device 3701 executing instructions from the memory 3742. As another example, the method 4900 may be performed by the processor 3703 of the computing device 3702 executing instructions from the memory 3704. [00363] The method 4900 includes, at 4902, obtaining model data specifying a three-dimensional (3D) model of an object. For example, the computing device 3702 of the 3D printer device 3701 of FIG. 37 may receive the model data 3707, which includes or corresponds to a 3D model of an object. To illustrate, the model data 3707 may represent the 3D model 4202 of FIG. 42.

[00364] The method 4900 includes, at 4904, processing the model data to generate a sliced model defining a plurality of layers to be deposited to form a physical model of the object, the plurality of layers including a first layer and a second layer. The second layer is above and in contact with the first layer, the first layer including a first region corresponding to a first material and a second region corresponding to a second material, and the second layer including a third region corresponding to the first material and a fourth region corresponding to the second material. For example, model data

representing the 3D model 4202 of FIG. 42 may be processed to generate the sliced model 4302 of FIG. 43. As described with reference to FIG. 46, the sliced model may include adjacent slices (e.g., a first slice and a second slice) corresponding to the first layer 4602 and the second layer 4604, respectively. The first layer 4602 includes the first region 4610 corresponding to the first material and includes the second region 4612 corresponding to the second material. Further, the second layer 4604 includes the third region 4620 corresponding to the first material and includes the fourth region 4622 corresponding to the second material.

[00365] The method 4900 includes, at 4906, generating machine instructions executable by a 3D printing device to deposit a portion of the first material corresponding to the first region and to the third region before depositing a portion of the second material corresponding to the second region and to the fourth region. For example, as described with reference to FIG. 46, first material may be deposited to form the first region 4610 and the third region 4620 before second material is deposited to form the second region 4612 and the fourth region 4622.

[00366] In some implementations, depositing the portion of the second material corresponding to the second region includes positioning a tip of an extruder associated with the second material below an upper surface of the first material. For example, as illustrated in FIG. 46, the tip 3731 of the syringe extruder 3730 may be inserted in the opening defined by layers of the first material 4504 to deposit the second material 4506 below an upper surface of the first material 4504.

[00367] FIG. 50 is a flowchart of a particular embodiment of a method 5000 that may be performed by one or more devices or components of the system 3700 of FIG. 37. For example, the method 5000 may be performed by the controller 3741 of the 3D printer device 3701 executing instructions from the memory 3742. As another example, the method 5000 may be performed by the processor 3703 of the computing device 3702 executing instructions from the memory 3704.

[00368] The method 5000 includes, at 5002, obtaining model data specifying a three-dimensional (3D) model of an object. For example, the computing device 3702 of the 3D printer device 3701 of FIG. 37 may receive the model data 3707, which includes or corresponds to a 3D model of an object. To illustrate, the model data 3707 may represent the 3D model 4202 of FIG. 42.

[00369] The method 5000 includes, at 5004, generating first machine instructions executable by a 3D printing device to generate a first portion of a physical model of the object by depositing material using a syringe extruder. The first machine instructions indicate a first value of a pressure setting, the pressure setting indicating a pressure to be applied to the syringe extruder. For example, the pressure setting may include a value stored in the settings 3750 that indicates a setting of the pressure regulator 3760 that controls fluid pressure applied to the plunger 3732 of the syringe extruder 3730 of FIG. 37. The first machine instructions may include a data field indicating the first value of the pressure setting. Alternatively, the first machine instruction may include information (such as a target flowrate, a target line width, a target line height, etc.) that the controller 3741 can use along with the pressure-flowrate data 3752 to determine the first value of the pressure setting.

[00370] The method 5000 includes, at 5006, generating second machine instructions executable by a 3D printing device to generate a second portion of the physical model of the object by depositing material using the syringe extruder. The second machine instructions indicate a second value of the pressure setting, the second value different from the first value. As with the first value of the pressure setting, the second value of the pressure setting may indicate a setting of the pressure regulator 3760 and may be included a data field of the second machine instruction or may be derived from information in the second machine instructions along with the pressure-flowrate data 3752.

[00371] In some implementations, the controller 3741, the computing device 3702, or another device may determine the pressure-to-flowrate data 3752 by determining a flowrate-to-pressure relationship of the material. To illustrate, one or more test prints may be performed by the 3D printer device 3701 to determine the flowrate-to-pressure relationship of the material. As another example, data specifying the flowrate-to-pressure relationship (e.g., rheology data) of the material may be provided to the computing device 3702, to the 3D printer device 3701, or to both, from an external source, such as a vendor of the material.

[00372] In some implementations, the flowrate-to-pressure relationship may be temperature dependent. For example, during operation, the 3D printer device 3701 may determine a temperature associated with the first printhead 3713 based on output of the temperature sensor 3733. The temperature associated with the first printhead 3713 may correspond to or be correlated with the temperature of the material. The temperature of the material may be used to select (e.g., from a look up table) or calculate the flowrate-to- pressure relationship of the material. In such an implementation, the first value of the pressure setting may be determined based on a first temperature associated with the material, and the second value of the pressure setting may be determined based on a second temperature (e.g., at a later time) associated with the material.

[00373] In some implementations, the value of the pressure setting may be determined (e.g., by the controller 3741) based on target characteristics of a line that is to be deposited. For example, the first value of the pressure setting may be determined based on a first target line width (or a first target line height) of the material, and the second value of the pressure setting may be determined based on a second target line width (or a second target line height)of the material. The first target line width (or the first target line height) may be different from the second target line width (or the second target line height). For example, in some circumstances, a larger (e.g., wider or taller) than normal line may be deposited in a particular location (e.g., to fill a space (as illustrated in FIG. 4) if the space is smaller than two normal-sized lines, but larger than one normal sized line. In this example, the second target line width (or the second target line height) may be greater than the first target line width (or the first target line height) but less than two times the first target line width (or the first target line height). To illustrate, the second target line width (or the second target line height) may be greater than the first target line width (or the first target line height) by a non-integer multiple. The pressure setting, velocity of the extruder, or both, may be controlled to deposit the larger than normal line.

[00374] In a particular embodiment, the syringe extruder 3730 has a first flowrate when the pressure setting has the first value and has a second flowrate (different than the first flowrate) when the pressure setting has the second value. In addition to or instead of controlling the pressure setting, the velocity of motion of the extruder may be controller to control characteristics (e.g., line width or line height) of deposited material. For example, the first machine instructions may include first instructions to cause the syringe extruder 3730 to move at a first speed while depositing the material, and the second machine instructions may include second instructions to cause the syringe extruder 3730 to move at the first speed while depositing the material. The first speed may be the same as or different from the second speed.

[00375] In some implementations, the material deposited by the syringe extruder

3730 may be deposited within an opening (or set of openings) formed in another material. For example, a third portion of the physical model may be associated with a second material and may define a first opening. In this example, the first value of the pressure setting may be selected to cause the syringe extruder to, during a single pass, substantially fill the first opening to form the first portion of the physical model. Likewise, in this example, a fourth portion of the physical model may be associated with the second material and may define a second opening. The second value of the pressure setting may be selected to cause the syringe extruder to, during a single pass, substantially fill the second opening to form the second portion of the physical model. The first opening may have a first width that is the same as or different from a second width of the second opening. To illustrate, as described with reference to FIGS 38A, 38B, 39A, 39B and 40, the pressure setting, the velocity of motion of the extruder, or both, may be varied to achieve various line widths (or line heights), e.g., to substantially fill an opening.

[00376] In another example, the third portion of the physical model (associated with the second material) may define an opening. During deposition of a portion of the material to form the first portion of the physical model, the syringe extruder may be offset from a wall of the first opening by an offset distance, as illustrated in FIG. 41. In this example, the first value of the pressure setting may be selected to cause the syringe extruder to deposit a line of the material having a line width equal to or greater than the offset distance, such as the line width 4106. In this example, the second line width may correspond to the second line width 4110, which may be used to form other lines of the material in the opening.

[00377] FIG. 51 is a flowchart of a particular embodiment of a method 5100 that may be performed by one or more devices or components of the system 3700 of FIG. 37. For example, the method 5100 may be performed by the 3D printer device 3701 (or one or more components thereof).

[00378] The method 5100 includes, at 5102, receiving machine instructions that enable generating a physical model of an object, the physical model including a plurality of layers that includes a first layer and a second layer. The second layer is above and in contact with the first layer. The first layer includes a first region corresponding to a first material and a second region corresponding to a second material, and wherein the second layer includes a third region corresponding to the first material and a fourth region corresponding to the second material. For example, the machine instructions may include or correspond to the commands 3709 of FIG. 37. The machine instructions specify operations to form a physical model of an object. For example, the object may correspond to the 3D model 4202 of FIG. 42. In this example, the 3D model 4202 may be sliced to form the sliced model 4302 of FIG. 43. The sliced model 4302 may be modified to form the modified sliced model 4402, which may be used to form machine instructions. The 3D printer device 3701 performing operations described by the machine instructions may deposit material corresponding to a plurality of layers 4508, which includes the first layer 4602 and the second layer 4604.

[00379] The method 5100 includes, at 5104, depositing, based on the machine instructions, a portion of the first material corresponding to the first region and to the third region. For example, the first material 4504 of FIG. 46 may be deposited to form the first region 4610 and the third region 4620.

[00380] The method 5100 includes, at 5102, after depositing the portion of the first material, depositing, based on the machine instructions, a portion of the second material corresponding to the second region and to the fourth region. For example, the second material 4506 of FIG. 46 may be deposited to form the second region 4612 and the fourth region 4622.

[00381] FIG. 52 is a flowchart of a particular embodiment of a method 5200 that may be performed by one or more devices or components of the system 3700 of FIG. 37. For example, the method 5200 may be performed by the 3D printer device 3701 (or one or more components thereof).

[00382] The method 5200 includes, at 5202, receiving first machine instructions associated with a first portion of a physical model of an object and second machine instructions associated with a second portion of the physical model. The first machine instructions indicates a first value of a pressure setting, the pressure setting indicating a first pressure to be applied to a syringe extruder, and the second machine instructions indicates a second value of the pressure setting, the second value different from the first value. For example, the machine instruction may include or correspond to the commands 3709 of FIG. 37. The machine instructions may specify values of one or more of the settings 3750. Alternately, the machine instructions may include information that is used by the controller 3741 to determine the values of the settings 3750. To illustrate, the machine instructions may include target line information, such as flowrate information, line height information, line width information, or other parameters related to flowrate. In this illustrative example, the controller 3741 may determine values of various settings, such as a pressure setting, a temperature setting, a velocity setting, etc., to achieve line parameters specified by the target line information. The various settings may be determined, for example, based on the pressure-flowrate data 3752, based on the calibration data 3748, or based on other information.

[00383] The method 5200 includes, at 5204, depositing, using the syringe extruder of a three-dimensional (3D) printer device, a portion of a material at a first flowrate to form the first portion based on the first machine instructions. For example, the syringe extruder 3730 may be used to deposit a first portion of a line having a first line width as described with reference to FIGS. 38A and 38B by setting a flowrate of the syringe extruder 3730 (based on a pressure setting of the pressure regulator 3760) and a velocity of motion of the syringe extruder 3730. As another example, the syringe extruder 3730 may be used to deposit the first portion of the line having a first line height as described with reference to FIGS. 39A and 39B by setting a flowrate of the syringe extruder 3730 (based on a pressure setting of the pressure regulator 3760) and a velocity of motion of the syringe extruder 3730.

[00384] The method 5200 includes, at 5206, depositing, using the syringe extruder, another portion of the material at a second flowrate to form the second portion based on the second machine instructions, the first flowrate different from the second flowrate. For example, the syringe extruder 3730 may be used to deposit a second portion of the line having a second line width as described with reference to FIGS. 38A and 38B by setting a flowrate of the syringe extruder 3730 (based on a pressure setting of the pressure regulator 3760) and a velocity of motion of the syringe extruder 3730. As another example, the syringe extruder 3730 may be used to deposit the second portion of the line having a second line height as described with reference to FIGS. 39A and 39B by setting a flowrate of the syringe extruder 3730 (based on a pressure setting of the pressure regulator 3760) and a velocity of motion of the syringe extruder 3730. [00385] The illustrations of the examples described herein are intended to provide a general understanding of the structure of the various implementations. The illustrations are not intended to serve as a complete description of all of the elements and features of apparatus and systems that utilize the structures or methods described herein. Many other implementations may be apparent to those of skill in the art upon reviewing the disclosure. Other implementations may be utilized and derived from the disclosure, such that structural and logical substitutions and changes may be made without departing from the scope of the disclosure. For example, method operations may be performed in a different order than shown in the figures or one or more method operations may be omitted. Accordingly, the disclosure and the figures are to be regarded as illustrative rather than restrictive.

[00386] Moreover, although specific examples have been illustrated and described herein, it should be appreciated that any subsequent arrangement designed to achieve the same or similar results may be substituted for the specific implementations shown. This disclosure is intended to cover any and all subsequent adaptations or variations of various implementations. Combinations of the above implementations, and other

implementations not specifically described herein, will be apparent to those of skill in the art upon reviewing the description.

[00387] The Abstract of the Disclosure is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, various features may be grouped together or described in a single implementation for the purpose of streamlining the disclosure.

Examples described above illustrate but do not limit the disclosure. It should also be understood that numerous modifications and variations are possible in accordance with the principles of the present disclosure. As the following claims reflect, the claimed subject matter may be directed to less than all of the features of any of the disclosed examples. Accordingly, the scope of the disclosure is defined by the following claims and their equivalents.