BUILD LAYERS AND MONITORING

RELATED APPLICATIONS

[0001] This application claims priority on U.S. Provisional Application No: 63/285,384 filed on December 2, 2021 , and entitled “ADDITIVE MANUFACTURING SYSTEM WITH ACCURATE BUILD LAYERS AND MONITORING”. As far as permitted, the contents of U.S. Provisional Application No. 63/285,384 are incorporated in their entirety herein by reference.

BACKGROUND

[0002] Metal, three-dimensional printing systems can be used to repair an existing object or fabricate an object from scratch. One type of metal, three-dimensional printing system is a Directed Energy Deposition system (“DED system”) that includes an energy source that generates an energy beam, and a nozzle that deposits the material that is fused together. In this system, the energy beam can melt the material at approximately the same time as the material is being deposited by the nozzle.

[0003] For the fabrication of an object from scratch, typically, a three-dimensional object model of the object is made with CAD software. Next, the three-dimensional object model is cut into a multitude of layers (“potential slices”) by slicer software to represent the various layers of material needed to be formed to make the object. Subsequently, the energy beam and the nozzle are controlled to sequentially form each of the layers to build the object.

[0004] Unfortunately, the thermal conditionals can change, and the material is not always accurately deposited during the building of each layer. This results in one or more inaccurate layers being built, and a geometry of the built object that is inaccurate. This can also influence the speed of the building process because either or both the energy beam and/or the material may not be properly focused because the layers are not being accurately built. There is a never ending search to improve the design of the DED system to improve the quality of the objects made by the DED system and the processing speed.

SUMMARY

[0005] The present embodiment is directed to a processing machine for building a three-dimensional object from an object model of the object using a plurality of sequential build layers, including a first build layer, a second build layer, a third build layer, and a fourth build layer. In one implementation, the processing machine includes: a build platform; a printer head that is controlled to print each of the build layers; a measurement system; and a control system. The printer head can include (i) a material supply that supplies material to build the built object; and (ii) an energy source which directs an energy beam at the material to melt the material and form each build layer. The measurement system measures a first layer build condition of the first build layer while it is being built and/or after it is built; and generates first layer measurement information related to the first build layer while it is being built and/or after it is built. The control system utilizes the first layer measurement information to create a second layer print parameters for the printer head to build the second build layer. Moreover, the control system can control the printer head using the second layer print parameters to build the second build layer.

[0006] As an overview, in this implementation, because the second layer print parameters are created based on the first layer measurement information, the second layer print parameters should be more accurate, the resulting second build layer should be more accurate, and errors in first build layer can be compensated for in the subsequent, second build layer.

[0007] This process of (i) measuring the previous build layer (while it is being built or after it is built), (ii) creating new print parameters for the next layer based on the measurement, and (iii) depositing (printing) the next build layer using the new print parameters, can be repeated for each subsequent build layer until the object is built. Stated differently, the print parameters for one or more build layers can be determined on the fly, (rather than pre-computed before fabrication begins) based on the measured build condition of the previously built, build layer. As a result thereof, the built, build layers will be more accurate, and errors in one or more previously built, build layers can be compensated for in the subsequent build layers.

[0008] In certain implementations, the measurement system can measure a second layer build condition of the second build layer and generate second layer measurement information related to the second build layer; and the control system can utilize the second layer measurement information to create third layer print parameters for the printer head to build the third build layer. Moreover, the control system can control the printer head using the third layer print parameters to build the third build layer.

[0009] Additionally, the measurement system can measure a third layer build condition of the third build layer (while it is being built or after it is being built), and generate third layer measurement information related to the third build layer; and the control system can utilize the third layer measurement information to create a fourth layer print parameters for the printer head to build the fourth build layer. Moreover, the control system can control the printer head using the fourth layer print parameters to build the fourth build layer.

[0010] In another implementation, a method for building a three-dimensional object from an object model of the object using a plurality of sequential build layers, includes: (i) providing a build platform; (ii) providing a printer head including a material supply that supplies material to build the built object; and an energy source which directs an energy beam at the material to melt the material; (iii) controlling the printer head to form the first build layer on the build platform with a control system; (iv) measuring a first layer build condition of the first build layer and generating first layer measurement information related to the first build layer; (v) creating second layer print parameters for the printer head to build the second build layer utilizing the first layer measurement information; and (vi) controlling the printer head using the second layer print parameters to form the second build layer on the build platform with the control system. [0011] In another implementation, a processing machine for building a three- dimensional object includes: (i) a build platform; (ii) a printer head that is controlled to form each of the build layers, the printer head having (a) a material supply that supplies material to build the built object; and (b) an energy source which directs an energy beam at the material to melt the material and form each build layer; (iii) a measurement system that measures a first layer build condition of the first build layer (during and/or after it is built) and generates first layer measurement information related to the first build layer; and (iv) a control system that utilizes slicing software to divide the object model into a plurality of potential slices; and wherein the control system utilizes the first layer measurement information to select at least one of the potential slices that is used to control the printer head to form the second build layer.

[0012] For example, the control system can utilize the first layer measurement information to select one of the potential slices from a first, second potential slice and a second, second potential slice.

[0013] Additionally, the control system can control the printer head to print the second build layer; the measurement system can measure a second layer build condition of the second build layer (during and/or after fully built), and generate second layer measurement information related to the second build layer; and the control system can utilize the second layer measurement information to select at least one of the potential slices that is used to control the printer head to form the third build layer. [0014] Moreover, the control system utilizes the second layer measurement information to select one of the potential slices from a first, third potential slice and a second, third potential slice.

[0015] In another implementation, a method for building a three-dimensional object includes: (i) dividing the object model into a plurality of potential second slices and a plurality of potential third slices with a control system; (ii) providing a build platform; (iii) providing a printer head including (a) a material supply that supplies material to build the built object; and (b) an energy source which directs an energy beam at the material to melt the material; (iv) controlling the printer head to form the first build layer on the build platform with the control system; (v) measuring a first layer build condition of the first build layer and generating first layer measurement information related to the first build layer; and (vi) selecting one of the potential second slices with the control system based on the first layer measurement information. [0016] Additionally, the method can include (i) controlling the printer head with the control system using the selected second slice to build the second build layer; (ii) measuring a second layer build condition of the second build layer and generating second layer measurement information related to the second build layer; (iii) selecting at least one of the potential third slices with the control system based on the second layer measurement information.

[0017] In another implementation, a processing machine for building a three- dimensional object includes: (i) a build platform; (ii) a printer head that is controlled to form each of the build layers, the printer head including (a) a material supply that supplies material to build the built object; and (b) an energy source which directs an energy beam at the material to melt the material and form each build layer; (iii) a measurement system that measures a first layer build condition of the first build layer and generates first layer measurement information related to the first build layer; and (iv) a control system that utilizes the first layer measurement information to determine a second layer print parameters for the printer head to build the second build layer.

[0018] For example, the control system can utilize the slicing software to divide the object model into a plurality of potential slices; and the control system can utilize the first layer measurement information to select one of the potential slices to determine the second layer print parameters.

[0019] In still another implementation, the processing machine includes (i) a build platform; (ii) a printer head that is controlled to print each of the build layers, the printer head including (a) a material supply that supplies material to build the built object; and (b) an energy source which directs an energy beam at the material to form a melt pool used to build each build layer; (iii) a measurement system that generates an image of the melt pool; and (iv) a control system that utilizes the image to adjust a position of the printer head relative to the build platform.

[0020] In yet another implementation, the processing machine includes: (i) a build platform; (ii) a printer head that is controlled to print each of the build layers, the printer head including (a) a material supply that supplies material to build the built object; and (b) an energy source which directs an energy beam at the material to melt the material and build each build layer; (iii) a measurement system that generates a plurality of images during the forming of the build layers; and (iv) a control system that analyzes the images to analyze the three-dimensional object.

[0021] In another implementation, the processing machine includes: (i) a build platform; (ii) a printer head that is controlled to form each of the build layers, the printer head including (a) an energy source configured to direct an energy beam to the built object to generate a melt pool on the built object; and (b) a material supply that supplies material to the melt pool to build the built object; (iii) a measurement system that generates first layer measurement information related to the first build layer; and (iv) a control system that utilizes slicing software to divide the object model into a plurality of slices that includes a first slice, and a second slice that is located above the first slice in the object model; and wherein the control system utilizes the first slice to form the first build layer and the control system utilizes the first layer measurement information to determine whether the second slice is used to control the printer head to form the second build layer. In this implementation, the second slice is positioned above the first slice along an axis (e.g., the vertical axis).

[0022] In another implementation, the method for building a three-dimensional object includes: (i) utilizing slicing software to divide the object model into a plurality of slices that includes a first slice, and a second slice that is located above the first slice in the object model; (ii) providing a build platform; (iii) providing a printer head that is controlled to form each of the build layers, the printer head including (a) an energy source configured to direct energy to the built object to generate a melt pool on the built object; and (b) a material supply that supplies material to the melt pool to build the built object; (iv) controlling the printer head with a control system that utilizes the first slice to form a first build layer; (v) generating first layer measurement information related to the first build layer with a measurement system; and (vi) utilizing the first layer measurement information to determine whether the second slice is used to control the printer head to form a second build layer.

[0023] In yet another implementation, the processing machine includes: (i) a build platform; (ii) a printer head that is controlled to form each of the build layers, the printer head including (a) an energy source configured to direct an energy beam to the built object to generate a melt pool on the built object; and (b) a material supply that supplies material to the melt pool to build the built object; (iii) a measurement system that generates first layer measurement information related to the first build layer; and (iv) a control system that utilizes slicing software to divide the object model into a plurality of potential slices; and wherein the control system utilizes the first layer measurement information to determine at least one of the potential slices that is not used to control the printer head to form the second build layer. In this design, unnecessary slices are skipped.

[0024] In still another implementation, the method for building a three-dimensional object includes: (i) utilizing slicing software to divide the object model into a plurality of potential slices; (ii) providing a build platform; (iii) providing a printer head that is controlled to form each of the build layers, the printer head including (a) an energy source configured to direct energy to the built object to generate a melt pool on the built object; and (b) a material supply that supplies material to the melt pool to build the built object; (iv) controlling the printer head to form a first build layer on the build platform with a control system; (v) generating first layer measurement information related to the first build layer; and (vi) utilizing the first layer measurement information to determine at least one of the potential slices that is not used to control the printer head to form the second build layer. In this design, unnecessary slices are not utilized. [0025] In another implementation, the processing machine includes: (i) a build platform; (ii) a printer head that is controlled to form each of the build layers, the printer head including (a) an energy source configured to direct an energy beam to the built object to generate a melt pool on the built object; and (b) a material supply that supplies material to the melt pool to build the built object; (iii) a measurement system that generates first layer measurement information related to the first build layer; and (iv) a control system that utilizes slicing software to divide the object model into a plurality of slices that includes a first slice, a second slice, and a third slice; and wherein the control system utilizes the first slice to form the first build layer and the control system utilizes the first layer measurement information to determine that at least the second slice is not used to control the printer head to form the second build layer.

[0026] In still another implementation, the processing machine includes (i) a build platform; (ii) a printer head that is controlled to print each of the build layers, the printer head including (a) an energy source configured to direct an energy beam to the built object to generate a melt pool on the built object; and (b) a material supply that supplies material to the melt pool to build the built object; (iii) a measurement system that generates thermal information of the melt pool; and (iv) a control system. In this example, the control system utilizes the thermal information to adjust at least one of (i) a position of the printer head relative to the build platform, (ii) a power of the energy beam, (iii) a scan speed of the energy beam relative to the built object which can be controlled by moving the printer head and/or the build platform, (iv) an off/on status of the energy source, (v) a beam focus distance of the energy beam, (vi) a deposition rate of the material by the material supply, and (vii) a deposition focus distance of the material supply.

[0027] Alternatively, the control system can utilize the image to adjust two or more of these build parameters on the fly.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The novel features of this embodiment, as well as the embodiment itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which:

[0029] Figure 1 is a simplified, side schematic view of a processing machine and an object being made;

[0030] Figure 2A is a simplified schematic that illustrates an object model with a plurality of planned, sequential potential slices, and a build frame with a first build layer deposited on the build frame;

[0031] Figure 2B is a simplified schematic that illustrates the object model with a second slice, and a build frame with two build layers;

[0032] Figure 2C is a simplified schematic that illustrates the object model with a third slice, and a build frame with three build layers;

[0033] Figure 2D is a simplified schematic that illustrates the object model with a fourth slice, and a build frame with four build layers;

[0034] Figure 3 is a flow chart that illustrates one method for building the object; [0035] Figure 4A is a simplified schematic that illustrates an object model with a plurality of potential slices, and a build frame with a first build layer deposited on the build frame;

[0036] Figure 4B is a simplified schematic that illustrates the object model with a second actual slice, and a build frame with two build layers;

[0037] Figure 4C is a simplified schematic that illustrates the object model with a third actual slice, and a build frame with three build layers;

[0038] Figure 5 is a flow chart that illustrates another method for building the object; [0039] Figure 6 is a side view of a build platform, a build frame, and a partly built object;

[0040] Figure 7A illustrates one non-exclusive example of a beam angle and a measurement angle;

[0041] Figure 7B is a simplified, non-exclusive example of a material supply having features of the present invention;

[0042] Figure 7C is a simplified perspective view of a partly built object;

[0043] Figure 7D is an alternative, simplified perspective view of the partly built object of Figure 7C with a melt pool;

[0044] Figure 7E is an enlarged view of the melt pool from Figure 7D;

[0045] Figure 7F is a view of a melt pool image;

[0046] Figure 8 is a simplified image of a built object, a combination melt pool image, and an enlarged portion of the combination melt pool image;

[0047] Figure 9 is a simplified image of another built object, another combination melt pool image, and an enlarged portion of the combination melt pool image; and [0048] Figure 10 is an enlarged view of a portion of the processing machine of Figure 1 .

DESCRIPTION

[0049] Figure 1 is a simplified, side schematic view of an implementation of a processing machine 10 that is used to fabricate/manufacture one or more three- dimensional objects 11. As provided herein, the processing machine 10 may be an additive manufacturing system such as a three-dimensional printer in which a material 12 (illustrated as small circles) is joined, melted, solidified, and/or fused together to manufacture one or more three-dimensional object(s) 11 .

[0050] A number of Figures include an orientation system that illustrates an X axis, a Y axis that is orthogonal to the X axis, and a Z axis that is orthogonal to the X and Y axes. It should be noted that any of these axes can also be referred to as the first, second, and/or third axes. Further, as used herein, movement with six degrees of freedom shall mean along and about the X, Y, and Z axes.

[0051] In certain non-exclusive implementations, the processing machine 10 includes (i) a build chamber 14 that defines a build space 14A; (ii) a build platform 16 that supports the object 11 while it is being built; (iii) a printer head 18 including a material supply 20 having one or more material directors 20A, and an energy source 22 (illustrated as a box in phantom) that generates an energy beam 22A (illustrated with an arrow); (iv) a measurement system 24 (illustrated as a box); and (v) a control system 26 (illustrated as a box) that cooperate to make each three-dimensional object 11 . The design of each of these components of the processing machine 10 may be varied pursuant to the teachings provided herein. Moreover, it should be noted that the positions of the components of the processing machine 10 may be different than that illustrated in Figure 1 . Further, it should be noted that the processing machine 10 may include more components or fewer components than illustrated in Figure 1 .

[0052] In Figure 1 , the processing machine 10 is a Directed Energy Deposition system (“DED system”), and the material director(s) 20A deposit the material 12 that is fused together, and the energy source 22 is controlled to melt the material 12 at approximately the same time as the material 12 is being deposited by the material director(s) 20A to build the object 11 .

[0053] For a DED system, to fabricate an object 11 from scratch, typically, an object model 232 (illustrated in Figure 2A) of the object 11 is made with CAD software. The object model 232 can be a three-dimensional object model. Alternatively, the object model 232 can be a two-dimensional object model, or just equations, code, or other data. The object model 232 can be provided to the control system 26, which subsequently controls the printer head 18 to print a plurality of sequential build layers 30 (illustrated with solid lines) used to build the object 11 . [0054] As an overview, the present invention includes a plurality of ways to improve the accuracy of one or more of the build layers 30. Stated another way, the control system 26 provided herein controls the printer head 18 in a fashion that improves the accuracy of one or more of the build layers 30. As a result thereof, the object 11 that is built will be more accurate.

[0055] Moreover, in certain implementations, the present invention provides an improved measurement system 24 that allows for better control of the printer head 18, and/or an improved method for analyzing the built object 11 . Moreover, the information from the measurement system 24 can be used to accurately control one or more of (e.g., all): (i) the position of the printer head 18 relative to the build platform 16; (ii) a power of the energy beam 22A; (iii) a scan speed of the energy beam 22A relative to the built object which can be controlled by moving the printer head and/or the build platform; (iv) an off/on status of the energy source 22; (v) a beam focus distance 31a of the energy beam 22A; (vi) a deposition rate of the material 12 (also referred to as supply speed or supply amount) by the material supply 20; (vii) a deposition focus distance 31 b of the material supply 20; and (viii) a position of the material supply 20 relative to the build platform 16. With this information, (i) the energy beam 22A is properly focused relative to the upper build layer 30 to accurately melt the material 12; and/or (ii) the material supply 20 is properly focused and controlled to accurately deposit the desired amount of material 12 in the desired position relative to the upper build layer 30.

[0056] The type of three-dimensional object(s) 11 manufactured with the processing machine 10 may be almost any shape or geometry. As a non-exclusive example, the three-dimensional object 11 may be a metal part, or another type of object, for example, a resin (plastic) part or a ceramic part, etc. The three-dimensional object 11 may also be referred to as a “part”. Further, the object 11 can be referred to as a “partially built object” while the material is being added, or as a “built object” when the object is fully formed.

[0057] In Figure 1 , object 11 is illustrated as still being printed. More specifically, in the simplified illustration of Figure 1 , the DED system 10 has printed seventeen, sequential build layers 30. However, the number of build layers 30 will depend upon the design of the object 11 and other factors. As alternative, non-exclusive examples, the object 11 can be built using at least 10, 100, 1000, 3000, 5000, 10,000, 30,000 or more adjacent build layers 30.

[0058] In Figure 1 , for ease of discussion, the build layers 30 can be labeled as a first build layer 30a, a second build layer 30b, a third build layer 30c, a fourth build layer 30d, etc. , moving from the bottom to the top of the object 11 . However, any of the build layers 30a-30d can be referred to as a first, second, third, fourth, etc., build layer. It should be noted that the first build layer 30a can alternatively be referred to as the “Nth layer”, the second build layer 30b can alternatively be referred to as the “N+1 layer”, the third build layer 30c can alternatively be referred to as the “N+2 layer”, the fourth build layer 30d can alternatively be referred to as the “N+3 layer”, and subsequent layers can be labeled in a similar fashion.

[0059] It should be noted that the term “build layer” can refer to a layer that is desired to be built, a layer that is actively being built, and/or a layer that was built (or formed).

[0060] The characteristics of each build layer 30 can be varied pursuant to the teachings provided herein. For example, each build layer 11 can have an X axis dimension measured along X axis, a Y axis dimension measured along the Y axis, and a Z axis dimension (“height”) measured along the Z axis. The value of the X axis dimension and the Y axis dimension for each build layer 30 can be varied as required to match the corresponding dimensions of the object model.

[0061] Further, as provided herein, the value of the Z axis dimension for each build layer 30 can be determined by the control system 26 and varied for each build layer 30. As alternative, non-exclusive examples, the printer head 18 can be controlled to print one or more of the build layers 30 having a Z axis dimension of approximately 10, 20, 50, 100, 200, or 500 microns.

[0062] The type of material 12 joined and/or fused together may be varied to suit the desired properties of the object(s) 11. As a non-exclusive example, the material 12 may include small metal particles for metal three-dimensional printing. Alternatively, the material 12 may be metallic material, non-metal material, a plastic, polymer, glass, ceramic material, or any other material known to people skilled in the art. The material 12 may also be referred to as “powder” in certain implementations. Alternatively, for example, the processing machine can be a wire feed system in which the material is a wire or filament that is melted to form the object 11 .

[0063] The build chamber 14 defines the build space 14A in which the object(s) 11 are formed. In one, non-exclusive implementation, the build chamber 14 is generally rigid box shaped, and forms a generally rectangular shaped, sealed, build space 14A. In Figure 1 , the build chamber 14 encloses the build platform 16, the printer head 18, and the measurement system 24, in addition to the object 11 that is being built. In this simplified example, the build platform 16 is coupled to the bottom, and the printer head 18 is coupled to the top of the build chamber 14. Alternatively, for example, (i) the build chamber 14 can have a different configuration (e.g., cylindrical shaped); and/or (ii) the build platform 16 and the printer head 18 can be positioned at different locations. [0064] Additionally, the build chamber 14 can include a chamber environmental controller 14B (illustrated as a box) that creates a controlled environment in the build chamber 14. In one implementation, the chamber environmental controller 14B creates a vacuum environment in the build chamber 14. Alternatively, the chamber environmental controller 14B can create a non-vacuum environment such as inert gas (e.g. helium gas, nitrogen gas, or argon gas) environment in the build chamber 14. In another, non-exclusive example, the chamber environmental controller 14B can selectively and individually create a non-oxidizing atmosphere in the chamber 14. Additionally, or alternatively, the chamber environmental controller 14B can selectively create a “local purge” controlled atmosphere (e.g., non-oxidizing) in a small region that includes the melt pool and new material 12 being added to the object 11. Additionally, or alternatively, the chamber environmental controller 14B can control a temperature in the build chamber 14.

[0065] For example, the chamber environmental controller 14B can include one or more heaters, coolers, vacuum pumps, gas supplies, filters, or fluid pumps to control the environment.

[0066] As used herein, the term “vacuum” shall mean any space in which the pressure is significantly lower than atmospheric pressure. In one embodiment, pressure in the range of approximately 1 torr to 1 e-3 torr is considered a “medium vacuum”. Further, pressure in the range of approximately 1 e-3 torr to 1 e-8 torr is considered a “high vacuum”. Additionally, pressure below 1 e-8 torr is considered an “ultra-high vacuum”.

[0067] It should be noted that the build chamber 14 can include one or doors (not shown) and/or load lock chambers (not shown) which allow access to the build space 14A, with or without, respectively, disturbing the controlled environment in the build chamber 14, to remove the built object 11 , for example.

[0068] The build platform 16 (directly or indirectly) supports the object 11 while each build layer 30 is being formed. In the non-exclusive implementation illustrated in Figure 1 , the build platform 16 includes a platform frame 16A, and a frame mover 16B (illustrated as a box) that selectively moves the platform frame 16A relative to the build chamber 14. Alternatively, for example, the build platform 16 can be designed without the frame mover 16B.

[0069] In certain implementations, each object 11 is built directly in/on the build platform frame 16A. Alternatively, one or more objects 11 can be built onto a movable build frame 28 (“build plate”) which is supported by and/or selectively coupled to the platform frame 16A. In Figure 1 , a single object 11 is built on each build frame 28. Alternatively, two or more objects 11 can be built on each build frame 28. With this design, the build frame 28 supports the material 12 while each object 11 is being formed. For example, each build frame 28 can be made of the same material as the material 12 used to build the object 11 or another suitable material. In certain implementations, the build frame 28 includes one or more frame features (not shown) that allow for the build frame 28 to be selectively coupled to the platform frame 16A. In one implementation, the object 11 is fused (e.g., welded) to the build frame 28 during the three-dimensional printing process. Alternatively, for example, the object 11 is not fused to the build frame 28 during the three-dimensional printing process.

[0070] In Figure 1 , the build frame 28 is generally flat shaped, e.g., flat disk shaped. Alternatively, for example, the build frame 28 can include side walls (not shown) that extend upward, or other features.

[0071] In the embodiment of Figure 1 , the platform frame 16A supports the build frame 28, and the platform frame 16A can optionally include one or more platform features (not shown) that selectively engage and selectively retain the build frame 28. [0072] The frame mover 16B can include one or more actuators. In one, nonexclusive implementation, the frame mover 16B can move the platform frame 16A and the build frame 28 up and down, back and forth and/or in rotation as necessary relative to the other components of the processing machine 10. Alternatively, or additionally, the other components of the processing machine 10 can be moved relative to the build frame 28.

[0073] The printer head 18 is controlled by the control system 26 to sequentially print the build layers 30 to form the object 11. The design of the printer head 18 can be varied pursuant to the teachings provided herein. In the non-exclusive implementation of Figure 1 , the printer head 18 includes a head frame 18A, a printer mover 18B, the material supply 20, and the energy source 22. Alternatively, the printer head 18 can be designed to include more or fewer components than are illustrated in Figure 1 .

[0074] The head frame 18A retains at least portion of the material supply 20 and the energy source 22. Further, at least a portion of the measurement system 24 can optionally be secured to and move with the head frame 18A. In the simplified illustration of Figure 1 , the head frame 18A is illustrated as being generally rectangular shaped. Alternatively, the head frame 18 can have a different configuration.

[0075] The printer mover 18B selectively moves and positions the head frame 18A with the material director(s) 20A, and at least a portion of the energy source 22. For example, the printer mover 18B can be designed and controlled to move the printer head 18 with six degrees of freedom (along and about the X, Y, and Z axes) relative to the build frame 28 and the build chamber 14 during the printing process for each build layer 30. Alternatively, the printer mover 18B can be designed and controlled to move the printer head 18 with fewer than six degrees of freedom (e.g., three degrees of freedom). For example, the printer mover 18B can include one or more linear motors, one or more rotary motors and/or one or more other actuators. In another nonexclusive implementation, the printer mover 18B can move the printer head 18 in two degrees of freedom (e.g., along the X and Y axes) and the frame mover 16B can move the platform frame 16A in one degree of freedom (e.g., along the Z axis). [0076] The material supply 20 supplies the material 12 that is used to build the object(s) 11 in the build chamber 14. The material supply 20 can deposit the material 12 while energy source 22 melts the material 12 to form each of the build layers 30. In one embodiment, the material supply 20 can include a material hopper (not shown) that retains the material 12, and one or more material directors 20A that direct the material 12 to the correct location to form each build layer 30. For example, each of the material directors 20A can be a nozzle which directs the material 12 at the desired location. Alternatively, for example, the material supply 20 can be wire feed system which feeds the material 12 as wire from one or more material spools (not shown) to each material director 20A. In some embodiments, the material directors 20A are mounted on the printer head 18 and connected by a conduit (e.g., a flexible hose) or other mechanism to direct the material 12 from a material supply (e.g., a powder hopper or spool of wire) which is not mounted on the printer head 18.

[0077] It should be noted that the number of material directors 20A can be varied. In Figure 1 , the material supply 20 is illustrated as having two material directors 20A. Alternatively, the material supply 20 can be designed to include more than two or just one material director 20A. In some embodiments, the printer head 18 may include multiple material directors 20A for different types of materials 12, such as one powder nozzle and one wire nozzle.

[0078] It should be noted that the control system 26 can control the material directors 20A to selectively control a deposition rate of the material 12 (also referred to as supply speed or supply amount) by the material supply 20 onto the build platform 16 and/or the uppermost layer.

[0079] Additionally, in one non-exclusive implementation, the material supply 20 can include a director mover assembly 20B that can be controlled by the control system 26 to selectively move and position the material directors 20A relative to the head frame 18A and/or the build platform 16. Stated in another fashion, the material focus distance 31 b of the material supply 20 can be adjusted by controlling the director mover assembly 20B that moves the material directors 20A relative to the other portions of the printer head 18 and the build platform.

[0080] For example, the director mover assembly 20B can include one or more actuators that selectively position the material directors 20A to selectively adjust the deposition focus distance 31 b of the material supply 20, and/or the position of the material directors 20A relative to the build platform 16 and/or the uppermost, previously built layer. In one implementation, the director mover assembly 20B can independently move (e.g., linearly or rotationally) each material director 20A.

[0081] In certain implementations, in the material supply 20, the material 12 is mixed into a carrier gas, and this mixture is directed from the one or more material directors 20A. As non-exclusive examples, the carrier gas can be nitrogen, argon, or another inert gas. With this design, a deposition rate of the material 12 by the material supply 20 to the build platform 16 can be increased or decreased by adjusting the carrier gas supply rate (quantity) and/or adjusting the quantity of material (ratio) that is mixed into the carrier gas.

[0082] The energy source 22 irradiates and melts the material 12 with the energy beam 22A to form each build layer 30. Stated in another fashion, the energy source 22 heats and melts the material 12 to form the object 30. In certain implementations, the energy source 22 may irradiate the beam 22A to a surface of the object 11 to generate a melt pool on surface of the object 11. The material supply 20 may supply the material 12 into the melt pool generated by the beam 22A.

[0083] In alternative non-exclusive implementations, the energy source 22 includes a beam generator 22B that generates (i) an electron beam 22A, (ii) a laser beam 22A, (iii) an ion beam 22A, or (iv) an electric arc 22A. In Figure 1 , the beam generator 22B is illustrated as being positioned within and movable with the head frame 18A. Alternatively, the beam generator 22B can be positioned away from the head frame 18A, and the energy beam 22A steered to exit from the head frame 18A. In certain implementations, the energy source 22 can be controlled to selectively adjust the beam focus distance 31 a, and/or selectively steer the energy beam 22A.

[0084] The measurement system 24 inspects and monitors each of the build layers 30 while each object 11 is being built. As non-exclusive examples, the measurement system 24 may include one or more elements such as a uniform illumination device, fringe illumination device, optical sensors, cameras that function at one or more wavelengths, lens, interferometer, or photodetector, or a non-optical measurement system such as an ultrasonic, eddy current, or capacitive sensor. Further, as discussed in more detail below, the measurement system 24 can include one or more thermal cameras and/or optical sensors. In one example, the sensors can provide measurement information. As a specific example, a thermal sensor can provide thermal information. This thermal information can be in the form of thermal images or arrays of information.

[0085] The control system 26 controls and directs power to the components of the processing machine 10 to build the three-dimensional object 11 from the computer- aided design (CAD) object model, by successively adding the build layers 30. The control system 26 may include one or more processors 26A and one or more electronic storage devices 26B.

[0086] The control system 26 functions as a device (CPU) that controls the operation of the processing machine 10 by executing one or more computer programs. The computer program(s) causes the control system 26 to perform the required operations. That is, this computer program is a computer program for making the control system 26 function so that the processing machine 10 will perform the operations provided herein. A computer program executed by the CPU may be recorded in a memory (that is, a recording medium) included in the control system 26, or an arbitrary storage medium built in the control system 26 or externally attachable to the control system 26, for example, a hard disk or a semiconductor memory. Alternatively, the CPU may download a computer program to be executed from a device external to the control system 26 via a network interface (not shown). Further, the control system 26 may not be disposed inside the processing machine 10, and may instead be arranged as a server or the like outside the processing machine 10, for example. In this case, the control system 26 and the processing machine 10 may be connected via a communication line such as a wired communications (cable communications), a wireless communications, or a network. In case of physically connecting with wired, it is possible to use serial connection or parallel connection of IEEE1394, RS-232X, RS-422, RS-423, RS-485, USB, etc. or 10BASE-T, 100BASE- TX, 1000BASE- T or the like via a network. Further, when connecting using radio, radio waves such as IEEE 802.1x, OFDM, or the like, radio waves such as Bluetooth (registered trademark), infrared rays, optical communication, and the like may be used. In this case, the control system 26 and the processing machine 10 may be configured to be able to transmit and receive various types of information via a communication line or a network. Further, the control system 26 may be capable of transmitting information such as commands and control parameters to the processing machine 10 via the communication line and the network. The processing machine 10 may include a receiving device (receiver) that receives information such as commands and control parameters from the control system 26 via the communication line or the network. As a recording medium for recording the computer program executed by the CPU, a CD- ROM, a CD-R, a CD-RW, a flexible disk, an MO, a DVD-ROM, a DVD-RAM, a DVD- R, a DVD + R, a DVD-RW, a magnetic medium such as a magnetic disk and a magnetic tape such as DVD + RW and Blu-ray (registered trademark), a semiconductor memory such as an optical disk, a magneto-optical disk, a USB memory, or the like, and a medium capable of storing other programs. In addition to the program stored in the recording medium and distributed, the program includes a form distributed by downloading through a network line such as the Internet. Further, the recording medium includes a device capable of recording a program, for example, a general- purpose or dedicated device mounted in a state in which the program can be executed in the form of software, firmware or the like. Furthermore, each processing and function included in the program may be executed by program software that can be executed by a computer, or processing of each part may be executed by hardware such as a predetermined gate array (FPGA, ASIC) or program software, and a partial hardware module that realizes a part of hardware elements may be implemented in a mixed form. In one, non-exclusive example, the control system 26 includes a first computer 26C that utilizes slicing software to divide the object model into a plurality of potential slices before building the three-dimensional object begins, and a second computer 26D which is used to control operation of the build platform 16 and the printer head 18 using the pre-computed potential slices. In this design, the computers 26C, 26D are illustrated side by side. Alternatively, the computers 26C, 26D can be remote from each other.

[0087] As provided above, thermal conditionals during the build process can change, the material 12 is not always accurately deposited during the building of each build layer 30, and/or the energy beam 22A is not always accurately controlled. This results in one or more inaccurate build layers 30 being formed.

[0088] As an overview, the present invention provides a plurality of ways in which the control system 26 can control the print process (e.g., the printer head 18) to improve the accuracy of one or more of the build layers 30 and the resulting build object 11.

[0089] For example, in one implementation, the measurement system 24 can measure one or more first layer build conditions (e.g., height and/or layer shape) for the first build layer 30a after it is deposited or while it is being built. Next, the control system 26 can generate second print parameters based on the first layer build condition(s) and subsequently control the printer head 18 to print the second build layer 30b based on the first layer build condition. Each print parameters data can be stored as G-Code file or another type of data file. Each potential slice 234 can be referred to as layer print parameters. As a result thereof, the second build layer 30b should be more accurate, and errors in first build layer 30a can be compensated for in the subsequent, second build layer 30b.

[0090] This process of (i) measuring the previous formed, build layer 30a, (ii) creating new print parameters for the next layer based on the measurement information, and (iii) depositing the next build layer 30 using the new print parameters, is repeated for each subsequent build layer 30 until the object 11 is built. As a result thereof, the build layers 30 should be more accurate, and errors in one or more previously formed, build layers 30 can be compensated for in the subsequently, build layers 30.

[0091] Stated in a different fashion, depending on the thickness and/or uniformity of the just completed (formed) build layer 30, the print parameters of the next build layer 30 may be adjusted to be a thin planar slice, a thicker slice, or may have a more complex 3D shape to compensate for any errors in the just completed (formed) build layer 30. As used herein, the term “print parameters” shall include one or more (e.g., all) of (i) the position of the printer head 18 relative to the build platform 16; (ii) a power of the energy beam 22A; (iii) a scan speed of the energy beam 22A relative to the built object which can be controlled by moving the printer head and/or the build platform; (iv) an off/on status of the energy source 22; (v) a beam focus distance 31a of the energy beam 22A; (vi) a deposition rate of the material 12 (also referred to as supply speed or supply amount) by the material supply 20; (vii) a deposition focus distance 31 b of the material supply 20; and (viii) a position of the material supply 20 relative to the build platform 16. The print parameters can also be referred to as a toolpath. With the present design, the print parameters for any given subsequent build layer can be selected and varied while building the subsequent build layer 30 to compensate for variations in the previous build layer 30. The accuracy of the object 11 will improve because the correct layer geometry is used for the actual deposition height. A cumulative height error will not occur.

[0092] As a result of this design, for example, the print parameters for one or more build layers 30 can be determined “on the fly” (i.e., while the object 11 is being built), based on the measured layer build condition of the previous build layer 30. Stated differently, the first build layer can be formed using the first layer print parameters. After the first build layer is formed, measurement information from the formed, first build layer can be used to determine the second layer print parameters necessary to build the second build layer. Next, after the second build layer is formed, measurement information from the formed, second build layer can be used to determine the third layer print parameters necessary to build the third build layer. This process of forming a build layer, capturing measurement information, and generating new print parameters for each subsequent build layer can be repeated until the object 11 is fully formed.

[0093] Figure 2A is a simplified schematic side illustration of a three-dimensional object model 232 for the object 11 (illustrated in Figure 1 ) that is to be built. In Figure 2A, the object model 232 is very simplified for clarity. Typically, the object model 232 is created by CAD software (for example).

[0094] For ease of discussion, Figure 2A also illustrates that the object model 232 can be cut into a plurality of planned, sequential potential slices 234 (illustrated with dashed lines) by slicer software used by the control system 26 (illustrated in Figure 1 ). In certain prior art designs, the entire object model 232 is sliced into the sequential potential slices 234 prior to printing the layers 230. However, it should be noted that in the implementation described in reference to Figures 2A-2D, the pre-slicing of the object model 232 into a plurality of potential slices 234 is not a necessary step. Instead, it is only necessary to generate the first potential slice 234a, with subsequent slices 234 generated on the fly.

[0095] The slicer software is computer software which converts the three- dimensional object model 232 to specific instructions on how to control the printer head 18 (illustrated in Figure 1 ). In some embodiments, the slicer software can divide the object model 232 into the stack of parallel and flat potential slices 234, and each potential slice 234 includes the print parameters (e.g., commands) for controlling the movement of the printer head 18 along the X and Y axes, controlling the energy source 22, and controlling the material supply 22, as well as a corresponding, desired target layer thickness (measured along the Z axis). For example, (i) the position of the printer head 18 relative to the build platform 16; (ii) the power of the energy beam 22A; (iii) the scan speed of the energy beam 22A relative to the built object which can be controlled by moving the printer head and/or the build platform; (iv) the off/on status of the energy source 22; (v) the beam focus distance 31a of the energy beam 22A; (vi) the deposition rate of the material 12 by the material supply 20; (vii) the deposition focus distance 31 b of the material supply 20; and (viii) the position of the material supply 20 relative to the build platform 16 can be controlled to try to achieve the desired target layer thickness and/or profile. In alternative embodiments, such as when the printer mover 18B and the frame mover 16B together provide three or more degrees of freedom, the potential slices 234 may have non-planar geometry and may not all be parallel to each other.

[0096] The potential slices 234 illustrated in Figure 2A, represent one possible way that the plurality of build layers 30 (illustrated in Figure 1 ) can be deposited to form the object 11 (illustrated in Figure 1 ). In the simplified illustration of Figure 2A, the object model 232 has been divided into a stack of twenty-one, sequential, potential slices 234. However, the number of potential slices 234 will depend upon the three-dimensional object model 232. As alternative, non-exclusive examples, the three-dimensional object model 232 can be sliced at slice increments (along the Z axis) of approximately 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, or 150 microns. However, the exact slice increments can be varied depending on the configuration of the object model 232.

[0097] In Figure 2A, for ease of discussion, the potential slices 234 can be labeled as a first slice 234a, a second slice 234b, a third slice 234c, a fourth slice 234d, etc., moving from the bottom to the top of the object model 232. However, any of the potential slices 234 can be referred to as a first, second, third, fourth, etc., potential slice.

[0098] Each potential slice 234 includes the print parameters used by the control system 26 to control the printer head 18 to print the corresponding build layer 230. Stated in a different fashion, each slice 234 can include the commands to control (i) the position of the printer head 18 relative to the build platform 16; (ii) the power of the energy beam 22A; (iii) a scan speed of the energy beam 22A relative to the built object which can be controlled by moving the printer head and/or the build platform; (iv) the off/on status of the energy source 22; (v) a beam focus distance 31a of the energy beam 22A; (vi) the deposition rate of the material 12 by the material supply 20; (vii) the deposition focus distance 31 b of the material supply 20; and (viii) the position of the material supply 20 relative to the build platform 16. The print parameters can include a G-Code file or another type of data file. Each potential slice 234 can be referred to as layer print parameters. For example, the first slice 234a can be referred to as first layer print parameters, the second slice 234b can be referred to as second layer print parameters, and the third slice 234c can be referred to as third layer print parameters, etc.

[0099] As provided above, the layer print parameters for one or more build layers 230 can be determined on the fly, based on the measured layer build condition of the previously formed, build layer 230. Thus, it may only be necessary at the start of the process to determine the first slice (first layer print parameters) 234a for the first build layer 230A, because subsequent layer print parameters will be determined based on the measured build condition of the previously formed, build layers 230. Thus, the potential slices 234 which are used to form the object 11 other than the first slice 234a will change based on how accurate each build layer 230 is formed. [00100] Figure 2A also illustrates the build frame 28 and that the first build layer 230A has been formed (built) on the build frame 28. In this example, the control system 26 has controlled the printer head 18 to print the first build layer 230A using the first layer print parameters from the first slice 234a.

[00101] As provided above, the environmental conditionals may not be completely accurate, the material 12 is not always accurately deposited, and/or the energy beam 22A may not be exactly focused during the building of each build layer 230. For example, even though the control system 26 has controlled the printer head 18 using the first layer print parameters to print the first build layer 230A, the first build layer 230a may not exactly match the first slice 234a.

[00102] For example, as illustrated in Figure 2A, the first slice 234a has a first target layer thickness (“height”) 236a (“also referred to as “first slice condition”) measured along the Z axis, and the formed, first build layer 230a has a first layer measured thickness (“height”) 238a (“also referred to as “first layer build condition”) measured along the Z axis. In this non-exclusive example, the first target layer thickness 236a is greater than the first measured layer thickness 238a. For example, the first target layer thickness 236a could have been 100 microns, but the first measured layer thickness 238a was actually 75 microns.

[00103] It should be noted that if the first build layer 230a was accurately printed (using the first layer print parameters) that the first measured layer thickness would be equal to the first target layer thickness. However, if the first build layer 230a was not accurately printed, the first measured layer thickness 238a can be greater than or less than the first target layer thickness 236a. Furthermore, it should be noted that the first layer measured thickness 238a may vary across (i.e., in the X and Y directions) the first build layer 230a.

[00104] In one implementation, the control system 26 uses the slicing software to determine the first slice 234a (first layer print parameters) for the printer head 18 to follow to build the first build layer 230a using the object model 232. Subsequently, after the first build layer 230a is formed or while the first build layer 230a is being formed, the measurement system 24 (illustrated in Figure 1 ) measures a first layer build condition 238a (e.g., the first measured layer thickness 238a) of the first build layer 230a and generates first layer measurement information related to the first build layer 230a. The layer build condition can include the measured layer thickness and/or the shape of the build layer.

[00105] Figure 2B is a simplified schematic side view of the three-dimensional object model 232 and a new second slice 234bn (illustrated with a dashed line) generate by slicer software used by the control system 26 (illustrated in Figure 1 ). As provided herein, the control system 26 utilizes the first layer measurement information from the first build layer 230a to create the new second slice 234bn that includes the new second layer print parameters for the printer head 18 to follow to build the second build layer 230b. In the non-exclusive example provided above, the first measured layer thickness 238a was 75 microns. Thus, the new second slice 234bn is calculated at a Z height within the object model 232 of 75 microns. In alternative embodiments, the control system 26 can select a potential slice for the second layer that corresponds to an expected mid-layer height of the second layer. For example, if the first measured layer thickness 238a is 75 microns and the second target layer thickness 236b is 100 microns, the expected mid-layer height of the second layer is 125 microns (75 microns + (100 microns)/2 = 125 microns) and the control system 26 can use the slicing software to generate a second slice 234bn calculated at a Z height within the part of 125 microns.

[00106] Comparing Figures 2A and 2B, the new, second slice 234bn in Figure 2B is different from the original second slice 234b in Figure 2A. This is because the new second slice 234bn was generated using the actual first layer measurement information. As a result thereof, resulting printed second build layer 230b should be more accurate.

[00107] The new second slice 234bn includes a new second layer print parameters (second layer printer commands) with deposition parameters selected to produce target thickness 236b used by the control system 26 to control the printer head 18 to print the second build layer 230b.

[00108] Figure 2B also illustrates the build frame 28, and that the second build layer 230b has been built on the first build layer 230a and the build frame 28. In this example, the control system 26 has controlled the printer head 18 to print the second build layer 230b with the target thickness 236b using the second layer print parameters from the new second slice 234bn.

[00109] It should be noted that even though the control system 26 has controlled the printer head 18 using the new second layer print parameters to print the second build layer 230b, the second build layer 230b may not exactly be accurate.

[00110] As illustrated in Figure 2B, the new second slice 234bn has a second target layer thickness (“height”) 236b measured along the Z axis, and the second build layer 230b has a second measured layer thickness (“height”) 238b measured along the Z axis. In this non-exclusive example, the second target layer thickness 236b is slightly greater than the second measured layer thickness 238b. For example, the second target layer thickness 236b could have been 120 microns, but the second measured layer thickness 238b was actually 110 microns.

[00111] It should be noted that if the second build layer 230b was accurately printed (using the new, second layer print parameters) that the second measured layer thickness 238b would be equal to the second target layer thickness 236b. However, if the second build layer 230b was not accurately printed, the second measured layer thickness 238b can be greater than or less than the second target layer thickness 236b. [00112] In this implementation, the control system 26 has used the slicing software to determine the new, second layer print parameters for the printer head 18 to build the second the second build layer 230b using the first layer measurement information. Subsequently, after the second build layer 230b was formed or while the second build layer 230b is being formed, the measurement system 24 (illustrated in Figure 1 ) measures a second layer build condition of the second build layer 230b and generates second layer measurement information related to the second build layer 230b. In this example, the second layer build condition can include the second measured layer thickness 238b, a current, overall build height 235, and/or the size and shape of the second build layer 230b.

[00113] Figure 2C is a simplified schematic side view of the three-dimensional object model 232 and a new potential, third slice 234cn (illustrated with a dashed line) generated by slicer software used by the control system 26 (illustrated in Figure 1 ). As provided herein, the control system 26 utilizes the second layer measurement information from the second build layer 230b to create the new third slice 234cn that include the new third layer print parameters for the printer head 18 to follow to build the third build layer 230c. In the non-exclusive example provided above, the overall build height 235 after the second build layer 230b is 185 microns. Thus, the new third slice 234cn is calculated at a Z height within the part of 185 microns.

[00114] Comparing Figures 2A and 2C, the new, third slice 234cn in Figure 2C is different from the original third slice 234c in Figure 2A. This is because the new third slice 234cn was generated using the actual second layer measurement information. As a result thereof, resulting third build layer 230c should be more accurate.

[00115] The new third slice 234cn includes a new third layer print parameters (third layer printer commands) with deposition parameters selected to produce the target thickness 236c used by the control system 26 to control the printer head 18 to print the third build layer 230c.

[00116] Figure 2C also illustrates the build frame 28, and that the third build layer 230c has been built on the second build layer 230b, the first build layer 230a and the build frame 28.

[00117] Similar to above, even though the control system 26 has controlled the printer head 18 using the new third layer print parameters to print the third build layer 230c, the third build layer 230c may not exactly match the new third slice 234cn.

[00118] As illustrated in Figure 2C, the new third slice 234cn has a third target layer thickness (“height”) 236c measured along the Z axis, and the third build layer 230c has a third measured layer thickness (“height”) 238c measured along the Z axis. For example, the third target layer thickness 236c could have been 100 microns, but the third measured layer thickness 238c was actually 90 microns.

[00119] It should be noted that if the third build layer 230c was accurately printed (using the new, third layer print parameters) that the third layer Z dimension 238c would be equal to the third target layer thickness (i.e. , slice Z dimension) 236c. However, if the third build layer 230c was not accurately printed, the third measured layer thickness 238c can be greater than or less than the third target layer thickness 236c.

[00120] In this implementation, the control system 26 used the slicing software to determine the new, third layer print parameters for the printer head 18 to build the third build layer 230c using the second layer measurement information. Subsequently, after the third build layer 230c was formed or while the third build layer 230c is being formed, the measurement system 24 (illustrated in Figure 1 ) measures a third layer build condition of the formed, third build layer 230c and generates third layer measurement information related to the third build layer 230c. In this example, the third layer build condition can include the third measured layer thickness 238c, a current, overall build height 235, and/or the size and shape of the third build layer 230c.

[00121] Figure 2D is a simplified schematic side view of the three-dimensional object model 232 and a new potential, fourth slice 234dn (illustrated with dashed lines) generate by slicer software used by the control system 26 (illustrated in Figure 1 ). As provided herein, the control system 26 utilizes the third layer measurement information from the formed third build layer 230c to create the new fourth slice 234dn that includes the new fourth layer print parameters for the printer head 18 to build the fourth build layer 230d. In the non-exclusive example provided above, the overall build height 235 after the third build layer 230c is 275 microns. Thus, the new fourth slice 234dn is calculated at a Z height within the part of 275 microns.

[00122] Comparing Figures 2A and 2D, the new, fourth slice 234cn in Figure 2D is different from the original fourth slice 234d in Figure 2A. This is because the new fourth slice 234dn was generated using the actual third layer measurement information. As a result thereof, the fourth build layer 230d should be more accurate.

[00123] Figure 2D also illustrates the build frame 28, and that the fourth build layer 230d has been built on the third build layer 230c, the second build layer 230b, the first build layer 230a and the build frame 28.

[00124] Similar to above, even though the control system 26 has controlled the printer head 18 using the new fourth layer print parameters to print the fourth build layer 230d, the fourth build layer 230d may not exactly match the new fourth slice 234dn.

[00125] As illustrated in Figure 2D, the new fourth slice 234dn has a fourth target layer thickness (“height”) 236d measured along the Z axis, and the fourth build layer 230d has a fourth measured layer thickness (“height”) 238d measured along the Z axis. [00126] It should be noted that if the fourth build layer 230d was accurately printed (using the new, fourth layer print parameters) that the fourth measured layer thickness 238d would be equal to the fourth target layer thickness 236d. However, if the fourth build layer 230d was not accurately printed, the fourth measured layer thickness dimension 238d can be greater than or less than the fourth target layer thickness 236d. [00127] In this implementation, the control system 26 used the slicing software to determine the new, fourth layer print parameters for the printer head 18 to follow to build the fourth build layer 230d using the third layer measurement information. Subsequently, after the fourth build layer 230d was formed or while the fourth build layer 230d is being formed, the measurement system 24 (illustrated in Figure 1 ) measures a fourth layer build condition of the fourth build layer 230d and generates fourth layer measurement information related to the fourth build layer 230d. In this example, the fourth layer build condition can include the fourth measured layer thickness 238d, a current, overall build height 235, and/or the size and shape of the fourth build layer 230d.

[00128] Figure 3 is a flow chart that illustrates one method for building the object described above in reference to Figure 2A-2D. In Figure 3, at step 300, the object model (CAD model) of the object is generated with CAD software. The object model can be stored as an STL file or other files. Other files may include a STEP file, an IGES file, a 3MF file, a DWG file, IS010303 file or a VRML file. Next, at step 302, the control system can use slicing software and the object model to generate a potential first slice. Subsequently, at step 304, the printer head (the energy beam and the nozzle) can be controlled by the control system to build the first build layer. Next, at step 306, the measurement system can measure a first layer build condition of the first build layer.

[00129] Subsequently, at step 308, the control system can use slicing software, the measured build condition, and the object model to generate the subsequent slice. Next, at step 310, the printer head can be controlled by the control system to build the next build layer. Subsequently, at step 312, the measurement system can measure a build condition of the just built layer. [00130] Next at step 314, the build condition can be compared to the object model to determine if the object is complete. If the object is not complete, steps 308-314 can be repeated until the object is finished at step 316.

[00131] It should be noted that the control system 26 can determine the second print parameters and each subsequent print parameters in an alternative fashion (described below with reference to Figures 4A-4C) than described above with reference to Figure 3. As an overview, the control system 26 can use the slicing software to divide the object model into a plurality of very thin (along the Z axis) potential slices. Subsequently, using measurement information from the previous build layer, the control system 26 can select the next potential slice and use the print parameters for the selected potential slice to build the subsequent build layer.

[00132] Figure 4A is a simplified schematic, side illustration of a three-dimensional object model 432 for the object 11 (illustrated in Figure 1 ) that is to be built. In Figure 4A, the object model 432 is similar to the object model 232 illustrated in Figure 2A.

[00133] Figure 4A also illustrates that the object model 432 can be cut into a plurality of potential slices 434 (illustrated with dashed lines) by slicer software used by the control system 26 (illustrated in Figure 1 ). However, in the non-exclusive example illustrated in Figures 4A, the object model 432 has been divided into a larger number of potential slices 434 than the object model 232 of Figure 2A. Stated in another fashion, the slicing software can be controlled to have relatively small slice increments 440 (measured along the Z axis). This results in many more potential slices 434. As used herein, the term “slice increment” shall mean the space between adjacent, potential slices 434 along the Z axis.

[00134] By using a smaller slice increment 440, the slicing software has created more potential slices 434 than are actually required to build the object 11. With this design, using the build conditions from the previous build layer, the control system 26 can select the best potential slice 434 to use to accurately build the subsequent build layer.

[00135] As provided herein, the slice increment 440 between adjacent slices 434 can be varied. As the slice increment 440 decreases, the number of potential slices 434 increases, and the number of unused potential slices 434 increases, but the ability to match the potential slice 434 to the measured build layer improves. As alternative nonexclusive implementations, the slice increment 440 can be one, five, ten, fifteen, twenty, thirty, forty, or fifty microns. In a specific example, the slice increment 440 can be twenty microns.

[00136] In certain implementations, the slice increment 440 is less than a target layer thickness for each build layer 430. As alternative, non-exclusive example, the slice increment 440 can be 10, 20, 30, 40 or 50 percent of the target layer thickness. In a specific example, the target layer thickness for each build layer 430 can be 100 microns, and the slice increment 440 can be 20 microns.

[00137] The potential slices 434 in Figure 4A represent one possible way that the object model 432 can be divided. However, the object model 432 can be divided in a different fashion than illustrated in Figure 4A.

[00138] In Figure 4A, for ease of discussion, the potential slices 434 can be labeled as a first potential slice 434a, a second potential slice 434b, a third potential slice 434c, a fourth potential slice 434d, a fifth potential slice 434e, a sixth potential slice 434f, a seventh potential slice 434g, an eighth potential slice 434h, a ninth potential slice 434i, a tenth potential slice 434j, etc., moving from the bottom to the top of the object model 432. However, any of the potential slices 434 can be referred to as a first, second, third, fourth, etc., potential slice.

[00139] In one example, if the slice increment 440 is twenty microns, (i) the first potential slice 434a will be at a Z height within the part of zero microns, (ii) the second potential slice 434b will be at twenty microns, (iii) the third potential slice 434c will be at forty microns, (iv) the fourth potential slice 434d will be at sixty microns, (v) the fifth potential slice 434e will be at eighty microns, (vi) the sixth potential slice 434f will be at one hundred microns, (vii) the seventh potential slice 434g will be at one hundred and twenty microns, (viii) the eighth potential slice 434h will be at one hundred and forty microns, (ix) the ninth potential slice 434i will be at one hundred and sixty microns, and (x) the tenth potential slice 434j will be at one hundred and eighty microns.

[00140] Each potential slice 434 includes the print parameters (printer commands) used by the control system 26 to control the printer head 18 to print a corresponding build layer 430. For example, the first slice 434a can include a first layer print parameters (printer commands) used by the control system 26 (illustrated in Figure 1 ) to control the printer head 18 (illustrated in Figure 1 ) to print a build layer 430 with a target thickness 436a that corresponds to the first slice 434a.

[00141] As provided above, the print parameters for one or more build layers 430 can be selected on the fly, based on the measured build condition of the previously build layer 430.

[00142] Figure 4A also illustrates the build frame 28 and that the first build layer 430a has been built on the build frame 28. In this example, the control system 26 has controlled the printer head 18 to print the first build layer 430a using the first print parameters of the first slice 434a.

[00143] As provided above, even though the control system 26 has controlled the printer head 18 using the first layer print parameters to print the first build layer 430A, the first build layer 430a may not be exactly accurate.

[00144] As illustrated in Figure 4A, the first slice 434a has a first target layer thickness (“height”) 436a measured along the Z axis, and the first build layer 430a has a first layer measured thickness (“height”) 438a measured along the Z axis. In this non-exclusive example, the first target layer thickness 436a is greater than the slice increment 440. Furthermore, the first target layer thickness 436a is greater than the first measured layer thickness 438a. For example, the first target layer thickness 436a could have been 80 microns, but the first measured layer thickness 438a is actually 40 microns.

[00145] It should be noted that if the first build layer 430a was accurately printed (using the first layer print parameters) that the first measured layer thickness would be equal to the first target layer thickness. However, if the first build layer 430a was not accurately printed, the first measured layer thickness 438a can be greater than or less than the first target layer thickness 436a.

[00146] In one implementation, the control system 26 uses the slicing software to determine the first layer print parameters for the printer head 18 to follow to build the first build layer 430a using the object model 432. Subsequently, after the first build layer 430a is formed or while the first build layer 430a is being formed, the measurement system 24 (illustrated in Figure 1 ) measures a first layer build condition (e.g., the first measured layer thickness 438a) and generates first layer measurement information related to the first build layer 430a. The layer build condition can include the measured layer thickness and/or the shape of the build layer.

[00147] Next, the control system 26 can utilize the first layer measurement information to select one of the potential slices 434 to use as the actual second slice. In the example described above, the first measured layer thickness 438a is 40 microns. Moreover, the third potential slice 434c is at forty microns. With the present design, the control system 26 can select the third potential slice 434c as the actual second slice 437 used to print the second build layer.

[00148] It should be noted that in this non-exclusive example, (i) the second potential slice 434b would have been selected if the first measured layer thickness 438a was approximately twenty microns; (ii) the fourth potential slice 434d would have been selected if the first measured layer thickness 438a was approximately sixty microns; (iii) the fifth potential slice 434e would have been selected if the first measured layer thickness 438a was approximately eighty microns; (iv) the sixth potential slice 434f would have been selected if the first measured layer thickness 438a was approximately one hundred microns; and (v) the seventh potential slice 434g would have been selected if the first measured layer thickness 438a was approximately one hundred and twenty microns. In alternative embodiments, the control system 26 can select a potential slice for the second layer that corresponds to an expected mid-layer height of the second layer. For example, if the first measured layer thickness 438a is 40 microns and the second target layer thickness 436b is 80 microns, the expected mid-layer height of the second layer is 80 microns (40 microns + (80 microns/2) = 80 microns) and the control system 26 can select the fifth potential slice 434e as the actual second slice 437 for the second build layer.

[00149] The method used by the control system 26 to select the actual second slice 437 from the potential slices 434 can be varied. For example, the control system 26 can select the potential slice 434 that is closest to the corresponding measured thickness 438a. If two potential slices 434 are equally close, the control system 26 can select the potential slice 434 that is larger or smaller. [00150] It should be noted that with the present design, the control system 26 utilizes the first layer measurement information to choose between at least two potential slices to select the actual second slice 437 used to print the second build layer.

[00151] Figure 4B is a simplified schematic side view of the three-dimensional object model 432 from Figure 4A with potential, slice 434a- 434j (illustrated with dashed lines). As provided herein, the control system 26 utilizes the first layer measurement information from the first build layer 430a to select the third potential slice 434c from the other potential slices 434 as the actual second slice 437.

[00152] Figure 4B also illustrates the build frame 28, and that the second build layer 430b has been built on the first build layer 430a and the build frame 28. In this example, the control system 26 has controlled the printer head 18 to print the second build layer 430b using the print parameters from the third potential slice 434c.

[00153] It should be noted that even though the control system 26 has controlled the printer head 18 using the layer print parameters to print the second build layer 430b, the second build layer 430b may not exactly be accurate.

[00154] As illustrated in Figure 4B, the actual slice 437 has a second target layer thickness (“height”) 436b measured along the Z axis, and the second build layer 430b has a second measured layer thickness (“height”) 438b measured along the Z axis. In this non-exclusive example, the second target layer thickness 436b is less than the second measured layer thickness 438b. For example, the second target layer thickness 436b could have been 100 microns, but the second measured layer thickness 438b was actually 104 microns, and the build height 435 is 144 microns.

[00155] In this implementation, the control system 26 has used the potential slices 434 to determine the actual second slice 437 for the printer head 18 to follow to build the second build layer 430b using the first layer measurement information. Subsequently, after the second build layer 430b was formed or while the second build layer 430b is being formed, the measurement system 24 (illustrated in Figure 1 ) measures a second layer build condition of the second build layer 430b and generates second layer measurement information related to the second build layer 430b. In this example, the second layer build condition can include the second measured layer thickness 438b, a current, overall build height 435, and/or the size and shape of the second build layer 430b.

[00156] Stated in another fashion, the control system 26 can utilize the second layer measurement information to select one of the potential slices 434 to use as the actual third slice. As provided above, the build height 435 is 144 microns. Thus, the control system 26 can select the eighth potential slice 434h because it is at a Z height within the part of one hundred and forty microns.

[00157] Figure 4C is a simplified schematic side view of the three-dimensional object model 432 from Figure 4A with potential, slice 434a- 434j (illustrated with dashed lines). As provided herein, the control system 26 utilizes the second layer measurement information from the second build layer 430a to select the eighth potential slice 434h from the other potential slices 434 as the actual third slice 437t.

[00158] Figure 4C also illustrates the build frame 28, and that the third build layer 430c has been built on the second build layer 430b, the first build layer 430a and the build frame 28. In this example, the control system 26 has controlled the printer head 18 to print the third build layer 430c using the print parameters from the eighth potential slice 434h.

[00159] It should be noted that even though the control system 26 has controlled the printer head 18 using the layer print parameters to print the third build layer 430c, the third build layer 430c may not exactly be accurate.

[00160] As illustrated in Figure 4C, the actual slice 437t has a third target layer thickness (“height”) 436c measured along the Z axis, and the third build layer 430c has a third measured layer thickness (“height”) 438c measured along the Z axis. In this non-exclusive example, the third target layer thickness 436c is greater than the third measured layer thickness 438c. For example, the third target layer thickness 436c could have been 100 microns, but the third measured layer thickness 438c was actually 90 microns, and the build height 435 is 234 microns.

[00161] In this implementation, the control system 26 has used the potential slices 434 to determine the actual third slice 437t for the printer head 18 to follow to build the third build layer 430c using the second layer measurement information. Subsequently, after the third build layer 430c was formed or while the third build layer 430c is being formed, the measurement system 24 (illustrated in Figure 1 ) measures a third layer build condition of the third build layer 430c and generates third layer measurement information. In this example, the third layer build condition can include the third measured layer thickness 438c, a current, overall build height 435, and/or the size and shape of the third build layer 430c.

[00162] With this design, the control system 26 can utilize the layer build condition from the previous build layer to select the actual slice from the potential slices 434 to generate the next layer.

[00163] Figure 5 is a flow chart that illustrates another method for building the object described above in reference to Figure 4A-4C. In Figure 5, at step 500, the object model (CAD model) of the object is generated with CAD software. Next, at step 502, the control system 26 or a separate computer can use slicing software and the object model to generate a plurality of potential slices having a small slice increment. Subsequently, at step 504, the printer head (e.g., the energy beam and the nozzle) can be controlled by the control system to build the first build layer. Next, at step 506, the measurement system can measure a first layer build condition of the formed, first build layer.

[00164] Subsequently, at step 508, the control system can select an actual slice from the plurality of potential slices based on the measured build condition. Next, at step 510, the printer head can be controlled by the control system to build the next build layer using the selected slice. Subsequently, at step 512, the measurement system can measure a build condition of the just-built layer.

[00165] Next at step 514, the build condition can be compared to the object model to determine if the object is complete. If the object is not complete, steps 508-514 can be repeated until the object is finished at step 516.

[00166] With this non-exclusive design, the problem of matching deposition thickness to the process head Z stepping in a DED 3D Printer is solved by (1 ) generating a high density set of potential slices before fabrication begins, (2) measuring the deposited material thickness of each build layer, and (3) selecting the next potential slice according to the Z height actually built and using that for deposition of the subsequent layer. The accuracy of the object will improve because the correct slice geometry is used for the actual deposition height.

[00167] A possible advantage over the method described in reference to Figures 4A- 4C compared with the method of Figures 2A-2D is that all operation of the slicing software is completed before part fabrication begins. In this way, the slicing software, which can be computationally expensive, can be performed by a separate first computer 26C (illustrated in Figure 1 ) independently of a second computer 26D (illustrated in Figure 2) which controls the operation of the processing machine 10. A possible advantage of the method of Figures 2A-2D is that fewer potential slices are required so the total computational load is reduced. Either method may be preferred depending on the computational resources available in a particular application.

[00168] Figure 6 is a simplified, side view of a build platform 616 including a build frame 628, and a partly built object 611 including a plurality of formed, build layers 630, such as a first build layer 630a, a second build layer 630b, a third build layer 630c, a n-1 build layer 630n-1 , and a n build layer 630n (moving from the bottom to the top). As provided herein, each build layer 630 has a layer thickness (“layer height”) 636, and the object 611 has an object build height 635 (along the Z axis) relative to the build frame 628 that increases with each added build layer 630. In Figure 6, for reference, (i) the first build layer 630a has a first layer thickness 636a, (ii) the second build layer 630b has a second layer thickness 636b, (iii) the third build layer 630c has a third layer thickness 636c, (iv) the n-1 build layer 630n-1 has a n-1 layer thickness 636n-1 , and (v) the n build layer 630n has a n layer thickness 636n.

[00169] In certain implementations, the measurement system 24 (illustrated in Figure 1 ) estimates the object build height 635 as each build layer 630 is being deposited (formed). For example, this information can be used to (i) generate/ select the correct print parameters for one or more subsequent build layers, (ii) adjust the relative position (focus distance) along the Z axis between the printer head 18 (illustrated in Figure 1 ) and the built object 611 , and/or (iii) estimate if there is a defect in the built object 611 . The design of the measurement system 24 can be varied pursuant to the teachings provided herein. In one implementation, the measurement system 24 includes one or more thermal cameras or other types of sensors. [00170] In another implementation, the present invention is directed to a nonexclusive system and method for in-situ monitoring of the melt pool and layer height of one or more of the build layers. In one implementation, the problem of in-situ part height measurement in a material-based metal additive manufacturing is solved by providing a measurement system that includes a camera that captures data relating to the melt pool and/or one or more of the build layers. For example, with reference to Figure 7, the measurement system 724 can be a thermal sensor, such as a thermal camera that includes a one- or two-dimensional array of sensors that capture thermal (e.g., infrared, visible, or ultraviolet light) radiation 724a emitted from the object 711 as it is being built to capture thermal information, e.g., thermal images 742. Subsequently, the camera data can be analyzed to locate the top of the melt pool surface, and compute its location in absolute z-coordinate.

[00171] Figure 7A illustrates the Z and Y axes of the orientation system, a partly built object 711 , and a simplified illustration of the printer head 718 including an energy source 722 and a thermal camera 724. Figure 7A also illustrates the beam focus distance 731a. In this design, the thermal camera 724 captures one or more thermal images 742 (illustrated in Figure 7F) of the object 711 as it is being built to estimate the location of the melt pool 740 (illustrated in Figures 7D and 7E) as each build layer 630 (illustrated in Figure 6) is being added and the build height 635 (illustrated in Figure 6) is the location of the melt pool 740 long Z axis. As used herein, the term “thermal image” shall include the generated thermal image 742 (e.g., displayed on a monitor), and/or a one- or two-dimensional array of data captured by the thermal camera 724. For example, the thermal camera 724 can include a one- or two-dimensional array of sensors that capture thermal (e.g., infrared, visible, or ultraviolet light) radiation 724a emitted from the object 711 as it is being built to create the thermal images 742.

[00172] The relative location of the thermal camera 724 and the energy source 722 can be varied. In the non-exclusive implementation of Figure 7A, (i) the thermal camera 724 is secured to and moves with the printer head 718, (ii) the thermal camera 724 receives the thermal radiation 724a from the object 711 at a measurement angle (“Ma”) 724b relative to the Z axis, and (ii) the energy beam 722A from the energy source 722 is directed at a beam angle (“Ba”) 722c relative to the Z axis at the object 711. In alternative embodiments, one or multiple thermal cameras 724 can be secured or moved independently from the printer head 718 and receives the thermal radiation 724a from the object 711 at different measurement angles.

[00173] In one, non-exclusive example, the beam angle 722c is approximately five degrees (Ba=5°), and the measurement angle 724a is approximately forty degrees (Ma=40°). However, the thermal camera 724 and the energy source 722 can have a different arrangement than illustrated in Figure 7A. In many embodiments, the energy beam 722A is aligned with the Z axis and the beam angle 722c is zero. In another implementation, the energy beam 722A can be moved to change the beam angle 722c. [00174] As provided in more detail below, in one, non-exclusive implementation, the measurement angle 724b, the beam angle 722c, and the captured thermal images 742, can be used to continuously monitor the build height 635 as the object 711 is being built.

[00175] In Figure 7A, only a single thermal camera 724 is illustrated. However, the measurement system can include multiple thermal cameras 724. The design of the thermal camera 724 can be varied. As non-exclusive examples, the thermal camera 724 can include a conventional camera calibrated for temperature, a high dynamic range (HDR) camera, a logarithmic camera, an infrared camera, an ultraviolet camera, or another type of thermal camera.

[00176] Figure 7B is a simplified, non-exclusive example of a material supply 720 including (i) the material directors 720A that directs the material 12 towards the build platform 16 (illustrated in Figure 1 ) or the uppermost layer; and (ii) the director mover assembly 720B which can move or position the material directors 720A to selectively adjust the deposition focus distance 731 B. Further, the deposition rate of the material 12 from the material directors 720A can selectively adjusted as dictated by the print parameters for a particular layer.

[00177] Figure 7C is a simplified perspective view of a partly built object 711 including a partly built, current, topmost build layer 736n and a previously built layer 736n-1 . It should be noted that a portion of the topmost build layer 736n is illustrated with dashed lines to represent the melt pool 740 that was created by the printer head 718 (illustrated in Figure 7A) during the printing of the topmost build layer 736n. [00178] Figure 7D is an alternative, simplified perspective view of the partly built object 711 of Figure 7C including the partly built, current, topmost build layer 736n with the melt pool 740, and the previously built layer 736n-1. Figure 7D also includes a dashed box 7E that is enlarged in Figure 7E.

[00179] Figure 7E is an enlarged view of the melt pool 740 from Figure 7D. In Figure 7E, a “X” represents the currently hottest portion (“Cn”) of the melt pool 740.

[00180] Figure 7F is a view of a thermal image 742 captured with the thermal camera 724 (illustrated in Figure 7A). In Figure 7F, an “X” was added to the thermal image 742 that represents the hottest spot Cn on this thermal image 742. In this embodiment, the hottest spot is determined by finding the pixel in the thermal image 742 with the highest value (i.e. , the brightest light).

[00181] As provided herein, in certain implementations, the control system 26 (illustrated in Figure 1 ) identifies the hottest portion (area) Cn of each captured thermal image 742, and subsequently utilizes the location of the hottest portion Cn (highest thermal temperature) to estimate the build height 635 (illustrated in Figure 6) at the time of the captured thermal image. In certain designs, the hottest portion Cn is considered (estimated to be) the highest portion of that build layer 736n at the time of the captured image 742. In other words, in certain implementations, the hottest point in the melt pool 740 is assumed to be where the energy beam 722A intersects the top surface of the melt pool 740. As the melt pool solidifies, this point becomes the top surface of the build layer 736n.

[00182] Moreover, as provided herein, using the known information of thermal sensor location, the view angle relative to the laser, and the highest signal of the melt pool location (Cn), the control system 26 can determine the location of the melt pool 740 top surface and the build height 635 along the Z axis. In this design, this location Cn is correlated to the top surface of the melt pool 740 to provide an accurate estimation of the build height 635. Stated in another fashion, the highest camera signal Cn is considered the top of the nth build layer.

[00183] The correlation between the thermal images of the melt pool 740 and the build height 635 can be determined with the following equations: Cn = E” _=i hi — dz * n] * (tan Ma° — tan Ba°) + offset Equation 1 C _n ~ C _n -i ⁼ (h _n ~ dz) * (tanMa° — tan Ba°) Equation 2 h _n = ^Cn ~^ ⁿ ~ ¹ - dz . Equation 3

In these equations, (i) C _n is the hottest spot (has the highest camera signal) in the thermal image 742; (ii) dz is the incremental z movement of the printer head between layers; (iii) h _n is the location of the thermal camera 740 along the Z axis at the nth layer; (iv) Ma is the measurement angle 724a; (v) Ba is the beam angle 722c; and (vi) a = tan Ma° - tan Ba°. The offset value is the initial relative position of the build frame 628 or the build platform 616 to the thermal camera 724. The offset value can be determined by heating the build frame 628 or the build platform 616 with the energy beam 722A at the start to initialize the system. Stated in another fashion, the offset value can be found out at the beginning of the data processing to identify the location of the build frame 628 or the build platform 616.

[00184] With this design, the measurement system 724 can be controlled to acquire detailed information on the object 711 while being built, such as (i) build height 635, (ii) layer thickness (height) by subtracting the previous layer height from the latest layer height; (iii) bonding between layers, and etc., in real-time without having to pause the process. This helps improve accuracy of the object and throughput.

[00185] As provided above, in one implementation, the measurement system 724 includes a thermal camera, and the proposed solution is a method to measure the location of melt pool and built height in additive manufacturing. The thermal camera 724 may be attached to the printer head 718 containing the energy source 722 so it can move in conjunction and observe the melt pool 740. The recordings will have information about the shape of the melt pool 740, which can be used to determine the build height 635.

[00186] Additionally, for example, the thermal images 742 (thermal information) from the thermal camera 724 can used to evaluate or predict defects in the built object 711. Stated in another fashion, the control system 26 can utilize multiple thermal images 742 captured during the build process to evaluate bonding between build layers, and detects in the build layers.

[00187] Figure 8 includes a simplified image of a built part 811 , a combination thermal image 844, and an enlarged portion 844p of the combination thermal image 844. The combination thermal image 844 of Figure 8 can be generated from a plurality of thermal images 742 captured by the thermal camera 724.

[00188] Somewhat similarly, Figure 9 is a simplified image of another built part 911 , another combination thermal image 944, and an enlarged portion 944p of the combination image 944. The combination thermal image 944 of Figure 9 can be generated from a plurality of thermal images 742 captured by the thermal camera 724. [00189] With reference to Figures 8 and 9, by evaluating the combination images 844, 944, the control system 26 can evaluate the quality of the build layer represented by the combination images 844, 944. Stated in another fashion, the thermal images 742 and/or the array of melt pool images 844, 944 can be composed and fed into an algorithm of the control system 26 to identify information related to the quality of the object 711 (and build layers), in-situ, while the object 711 is being built. The images 742, 844, 944 can be used to identify defects in the object 711 while it is being built.

[00190] As illustrated in Figure 8, the combination image 844 shows only minor inconsistencies in the characteristics of melt pool during the build. These defects can be caused by the acceleration and deceleration of the printer head 18 during the building process causing differences in material amount as well as energy density at each end.

[00191] In contrast, in Figure 9, the combination image 944 shows more obvious defects in characteristics of melt pool during the build. In other words, the individual images 742 within combination image 944 show a large amount of variation in size, shape, and location. The combination image 944 can be used to determine that this object 911 has actual defects.

[00192] With reference back to Figure 7A, the thermal camera 724 can be used to estimate the beam focus distance 731 a between the energy source 722 and the material supply 20 (illustrated in Figure 1 ), and the topmost build layer of the object 711. With this information, for example, the printer mover 18B (illustrated in Figure 1 ) can be used to make in-situ Z-pitch adjustment to the beam focus distance 731 a to the energy source 722 and/or the material supply 20.

[00193] As provided herein, ideally, three-dimensional printing machines should operate at a target beam focus distance 731a between the energy source 722 and the object 711 and/or at a target deposition focus distance 731 b between the exits of the material supply 720 to the object 711 based on the desired spot size and layer thickness. However, as multiple layers build up, the thermal conditions change as well as the print characteristics (e.g., layer thickness, width, etc.) change. For the processing machine 10 of Figure 1 , if the printed layer is thicker or thinner than the previous layer, the process head location should be adjusted accordingly to control the focus distance.

[00194] As provided above, from the thermal images 742, the distance between the layer being built and the printing head 718 can be estimated. This information can be fed into the control system 26 so that (i) the position of the printer head 718 with the energy source 722, can actively controlled to move up or down to maintain the desired beam focus distance 731 a; and/or (ii) the material directors 720A can be controlled and positioned by the director mover assembly 720B to maintain the desired material focus distance 731 b.

[00195] This real time adjustment to the beam focus distance 731 a, and/or material focus distance 731 b can be used in any three-dimensional printing system, regardless of the energy source 722, the material supply 20 or the material directors 20A.

[00196] As provided herein, one or more print parameters of one or more build layers can be adjusted in real time, on the fly, based on the information from the measurement system, including the thermal camera 724.

[00197] Figure 10 is an enlarged view of a portion of the processing machine 10 of Figure 1 including a portion of the printer head 18, the energy source 22, the material supply 20, and the measurement system 24. Additionally, a portion of the currently topmost build layer 30T is shown in Figure 10.

[00198] In certain implementations, the measurement system 24 captures one or more thermal images that are used by the control system 26 (illustrated in Figure 1 ) to dynamically adjust one or more of the following build conditions (parameters): Moreover, the information from the measurement system 24 can be used to accurately control one or more of (e.g., all): (i) the position of the printer head 18 relative to the topmost layer 30T and the build platform 16 (illustrated in Figure 1 ); (ii) a power of the energy beam 22A; (iii) the scan speed of the energy beam 22A (e.g., rate of movement between the topmost layer 30T and the energy beam 22A); (iv) the off/on status of the energy source 22; (v) the beam focus distance 31a of the energy beam 22A; (vi) the deposition rate of the material 12 (also referred to as supply speed or supply amount) by the material supply 20; (vii) the deposition focus distance 31 b of the material supply 20; and (viii) the position of the material directors 20A relative to the topmost layer 30T and the build platform 16 (e.g., with the director mover assembly 20B).

[00199] It should be noted that the control system 26 (illustrated in Figure 1 ) can be designed to dynamically adjust one, two, three, four, five, six, seven, or all eight of these build conditions on the fly based on the feedback from the measurement system 24

[00200] With this design, (i) the energy beam 22A is properly focused relative to the upper build layer 30 to accurately melt the material 12; and/or (ii) the material supply 20 is properly focused and controlled to accurately deposit the desired amount of material 12 in the desired position relative to the upper build layer 30.

[00201] As a non-exclusive examples, (i) the beam focus distance 31 a of the energy beam 22A can be increased or decreased by controlling the printer mover 18B (illustrated in Figure 1 ) and/or the frame mover 16B (illustrated in Figure 1 ); (ii) the power of the energy beam 22A can be increased or decreased by controlling the energy generator (energy source) 22B; (iii) the scan speed of the energy beam 22A can be increased or decreased by controlling the energy generator 22B, the printer mover 18B, and/or the frame mover 16B; (iv) the off/on status of the energy generator 22B can be controlled by a signal form the control system 26; (v) the deposition rate of the material 12 by the material supply 20 to the topmost build layer 30T can be increased or decreased by adjusting the gas supply rate (quantity) and/or adjusting the material rate (quantity); (vi) the material focus distance 31 b can be increased or decreased by controlling the director mover assembly 20B, the printer mover 18B (illustrated in Figure 1 ) and/or the frame mover 16B.

[00202] In the non-exclusive implementation of Figure 10, the beam focus distance 731a and the material focus distance 731 b can be independently adjusted using the director mover assembly 20B and the printer mover 18B (illustrated in Figure 1 ). Alternatively, machine can be designed without independent adjustment of the beam focus distance 731 a and the material focus distance 731 b.

[00203] As provided herein, from the thermal images, the distance between the topmost layer 30T being built and the printing head 18 can be estimated. This information can be fed into the control system 26 to dynamically adjust one or more of the build conditions described above.

[00204] This real time adjustment can be used in any three-dimensional printing system, regardless of the energy source 22, and the material supply 20.

[00205] Those of ordinary skill in the art will realize that the following detailed description of the present embodiment is illustrative only and is not intended to be in any way limiting. Other embodiments of the present embodiment will readily suggest themselves to such skilled persons having the benefit of this disclosure. Reference will now be made in detail to implementations of the present embodiment as illustrated in the accompanying drawings.

[00206] In the interest of clarity, not all of the routine features of the implementations described herein are shown and described. It will, of course, be appreciated that in the development of any such actual implementation, numerous implementationspecific decisions must be made in order to achieve the developer's specific goals, such as compliance with application-related and business-related constraints, and that these specific goals will vary from one implementation to another and from one developer to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of engineering for those of ordinary skill in the art having the benefit of this disclosure.