BACKGROUND

[0001] The present disclosure relates to additive fabrication, which may also be known as additive manufacturing. Additive manufacturing involves forming a desired geometry layer-by-layer under computer control. For example, a layer of powder metal alloy or other material is deposited into a bed. Selected portions of the layer are then fused, such as by laser, according to a particular cross section of the component. The process is repeated until the entire component is built, layer-by-layer, from the bottom up. In other variations of additive manufacturing, a printer device and printer head are used to selectively deposit an "ink" or polymer material layer-by-layer.

SUMMARY

[0002] An additive fabrication process according to an example of the present disclosure includes rotating a core member about a central axis; while the core member is rotating, selectively depositing a first material onto the core member with respect to computerized design data representing an article to form a first radial layer of the article; and while the core member with the first radial layer is rotating, selectively depositing a second material onto the first radial layer with respect to the computerized design data to form a second radial layer of the article.

[0003] In a further embodiment of any of the forgoing embodiments, the first material is a metal-based material and the second material is a polymer-based material.

[0004] In a further embodiment of any of the forgoing embodiments, the polymer- based material includes additive particles selected from the group consisting of magnetically active additive particles, thermal conductivity modifier additive particles, and combinations thereof.

[0005] In a further embodiment of any of the forgoing embodiments, the selective depositing of the first material includes forming a coil of metal-based material with a constant spacing between turns of the coil of metal-based material.

[0006] In a further embodiment of any of the forgoing embodiments, the selective depositing of the second material includes forming a coil of polymer-based material. The coil of polymer-based material is substantially closed with regard to any spacing between turns of the coil of polymer-based material. [0007] A further embodiment of any of the forgoing embodiments includes selectively depositing one or more additional first radial layers and additional second radial layers with respect to the computerized design data.

[0008] In a further embodiment of any of the forgoing embodiments, the selective depositing of the first material, the selective depositing of the second material, or a combination thereof includes leaving at least one open space in the form of a continuous, open-ended passage in the article.

[0009] In a further embodiment of any of the forgoing embodiments, the continuous passage extends through at least one of the first radial layers and through at least one of the second radial layers.

[0010] In a further embodiment of any of the forgoing embodiments, the selective depositing of the first material, the selective depositing of the second material, or a combination thereof includes leaving at least one open space in the form of a controlled- geometry void.

[0011] A further embodiment of any of the foregoing embodiments includes installing an electronic device in the controlled-geometry void.

[0012] In a further embodiment of any of the forgoing embodiments, the selective depositing of the first material, the selective depositing of the second material, or a combination thereof includes forming the one or more additional first radial layers and additional second radial layers over the electronic device.

[0013] In a further embodiment of any of the forgoing embodiments, the selective depositing of at least one of the first material or of the second material includes extruding.

[0014] An article according to an example of the present disclosure includes a first radial layer formed of a first material. The first radial layer is disposed around a central axis in a first radial layer geometry that corresponds to computerized design data of the article, and a second radial layer is formed of a second material. The second radial layer is disposed around the first radial layer in a second radial layer geometry that corresponds to the computerized design data of the article.

[0015] In a further embodiment of any of the forgoing embodiments, the first material is a metal-based material and the second material is a polymer-based material.

[0016] In a further embodiment of any of the forgoing embodiments, the polymer- based material includes additive particles selected from the group consisting of magnetically active additive particles, thermal conductivity modifier additive particles, and combinations thereof. [0017] In a further embodiment of any of the forgoing embodiments, the first radial layer is in a form of a coil of metal-based material with a constant spacing between turns of the coil of metal-based material, and the second radial layer is in the form of a coil of polymer-based material that is closed with regard to any spacing between turns of the coil of polymer-based material.

[0018] In a further embodiment of any of the forgoing embodiments, at least one of the first radial layer and the second radial layer includes a continuous, open-ended passage.

[0019] A further embodiment of any of the foregoing embodiments includes one or more additional first radial layers and additional second radial layers in an alternating layer arrangement, and an electronic device embedded in the alternating layer arrangement.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The various features and advantages of the present disclosure will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows. In this disclosure, like reference numerals designate like elements where appropriate and reference numerals with the addition of one-hundred or multiples thereof designate modified elements that are understood to incorporate the same features and benefits of the corresponding elements.

[0021] Figure 1 illustrates an example rotary additive fabrication process.

[0022] Figure 2 illustrates a modification of the process of Fig. 1.

[0023] Figure 3 illustrates another modification that utilizes a polymer-based material with additive particles.

[0024] Figure 4 illustrates an example article fabricated in accordance with an example process disclosed herein to have an alternating layer arrangement.

[0025] Figure 5 illustrates another example process and article that has a continuous, open-ended passage.

[0026] Figure 6 illustrates another example process and article that has a controlled-geometry void and embedded electronic device.

DETAILED DESCRIPTION

[0027] Figure 1 schematically illustrates an example additive fabrication process 20. As will be described, the disclosed process 20 is a rotary technique that can be used to build an article layer-by-layer, radially inwards out, to fabricate electromagnetic devices and the like. [0028] Although not specifically limited, the process 20 will be described herein with regard to hardware and/or software for carrying out the process 20. It is to be understood, however, that the hardware and software could vary depending on factors such as the article being formed and the types of deposition techniques selected for use. In the illustrated example, the process 20 utilizes a first feeder 22, a second feeder 24, a rotary mechanism 26, and a controller 28 that is in communication with the first feeder 22, the second feeder 24, and the rotary mechanism 26 for controlling operation thereof. For instance, the controller 28 includes software, hardware (e.g., a microprocessor, display, etc.), or both to control the position and feed rates of the feeders 22/24 and the rotational speed of the rotary mechanism 26. The controller 28 can thus coordinate the operations of these components to carry out the process 20 and functions described herein.

[0029] The rotary device 26 rotates a core member 30 about a central axis A. While the core member 30 is rotating, the first feeder 22 selectively deposits a first material 32 onto the core member 30 with respect to computerized design data that represents the article that is being formed in order to deposit or form a first radial layer 32a of the article. Again, while the core member 30 is rotating, the second feeder 24 selectively deposits a second material 34 onto the first radial layer 32a with respect to the computerized design data to form a second radial layer 34a of the article. As can be appreciated, additional radial layers 32a/34a may be deposited in an alternating arrangement to form a multilayer, functional device, such as but not limited to, an electromagnetic device. The materials 32/34 may be the same in composition, but more typically would be different compositions to build layers of different functionality, such as but not limited to, insulating and conductive layers. Additionally, although the two feeders 22/24 are shown, a single feeder may alternatively be used to deposit the first material 32 and then the second material 34.

[0030] The computerized design data may be Computer Aided Design (CAD) data or other computerized data that represents a portion or all of the geometry of the article. The controller 28 may include the computerized design data or, alternatively, may be responsive to another controller or the like that has the computerized design data.

[0031] The first feeder 22, the second feeder 24, or both can be selected to deposit the first material 32 and the second material 34 in a desired geometry or configuration. As an example, the first feeder 22 may be a wire feeder that feeds a wire of the first material 32 onto the core member 30. The second feeder 24 may be an extruder that extrudes a filament of the second material 34 onto the first radial layer 32a. However, as can be appreciated, in other examples, the first feeder 22, the second feeder 24, or both can employ other deposition techniques of the first and second materials 32/34. For example, the first and second feeders 22/24 may be configured to feed the first and second materials 32/34 as a spray, slurry, gel, paste, film, ink, or the like. Alternatively or additionally, the first and second feeders 22/24 can feed the first and second materials 32/34 in different cross-sectional geometries and/or at different volumes. Furthermore, additional feeders and materials can be used to deposit additional layers or types of layers.

[0032] The controller 28 is configured/programmed to control the rotational speed of the core member 30 via rotary mechanism 26 and the deposition location and rate of the first and second materials 32/24 via feeders 22/24. For instance, the rotation of the core member 30 and the deposition location and rate are controlled to control the surface finish of the first radial layer 32a, the second radial layer 34a, or both. For example, rotation of the core member 30 and deposition of the first and second materials 32/34 may periodically be ceased or slowed for a predetermined amount of time to facilitate controlling surface finish of one or more of the layers 32a/34a.

[0033] The feeders 22 and 24 can be employed simultaneously to deposit the first and second materials 32/34 simultaneously and thus form the first and second radial layers 32a/34a simultaneously (but axially offset). However, in other examples, the selective deposition of the first and second materials 32/34 may be separated in time such that the first material 32 is first deposited to partial or full completion and the second material 34 is thereafter deposited to partial or full completion. Additionally, the rotational direction of the core member 30 may be reversed for one of more of the layers 32a/34a to provide an opposite winding or coil direction. Although the first and second materials 32/34 are deposited such that the first and second layers 32a/34a are in contact in the illustrated example, it will be appreciated that intermediate layers or structures could be provided radially in between the layers 32a/34a such that they do not contact or are in partial contact. Furthermore, the first and second materials 32/34, and thus the first and second layers 32a/34a, could be reversed in radial order.

[0034] Figure 2 depicts a further example of the process 20. In this example, the first material 132 is a metal -based material and the second material 134 is a polymer-based material. For instance, the polymer-based material is a thermoplastic or a thermoset. In further examples, the metal-based material is based on Ni, Cu, Au, or Ag, and the polymer- based material is based on epoxy, acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), nylon, polycarbonate (PC), or silicone. In the end-use article, the first radial layer 132a may thus serve as an electric current carrier and the second radial layer 134a may serve as an electric insulating layer. As used herein, the term "-based" used with reference to one or more materials refers to the composition of the material having a predominant amount of that constituent upon which it is based. Thus, a polymer-based material and a metal-based material will have predominant amounts of, respectively, polymer and metal relative to the individual amounts of any other constituents in the compositions.

[0035] In a further example, because the process 20 is controlled in accordance with the computerized design data, the location and rate of the deposition of the first material 132 and the second material 134 can be precisely controlled. For instance, the first material 132 is selectively deposited as a coil of the metal-based material with a constant spacing, represented at "a," between turns of the coil of the metal-based material. A uniform helical coil is one example. That is, the location on the core member 30 that the first material 132 is deposited is precisely controlled to achieve a relatively constant spacing and thus high concentricity about the axis A and enhanced performance of the end-use article.

[0036] In the illustrated example, the second material 134 is also selectively deposited as a coil, but of the polymer-based material. The polymer coil is generally closed with regard to any spacing between the turns of the coil. Thus, the successive turns of the coil are in contact with each other such that the second radial layer 134a is substantially free of any voids or holes. Again, because the process 20 is controlled with regard to the computerized design data, the location and rate of deposit of the second material 134 is highly accurate, and the turns of the coil can be precisely controlled to potentially reduce voids or holes in the second radial layer 134a.

[0037] Figure 3 illustrates a further example in which the second material 234 is a polymer-based material that includes additive particles 236 to enhance the functionality of the second radial layer 234a. For example, the additive particles 236 are selected from magnetically active additive particles, thermal conductivity-enhancing additive particles, or combinations thereof. Magnetically active additive particles are magnetic materials with a high permeability used to confine and guide magnetic fields. Non-limiting examples of magnetically active particles include nickel-iron-chromium alloy, iron, soft and hard ferrite, cobalt, some alloys of rare earth metals and certain ceramics. Thermal conductivity modifier additive particles are particles that modify thermal conductivity of the second radial layer 234a by, for example, either increasing or decreasing thermal conductivity of the polymer of the polymer-based material (e.g., carbon nanotubes, boron nitride, graphene, aluminum oxide, silicon carbide, aluminum nitride, glasses and ceramics). That is, the thermal conductivity additive particles have either a higher or lower thermal conductivity than the polymer. In a further example, the difference in thermal conductivity between that of the polymer and that of the thermal conductivity additive particles is at least +/- 10%. In additional examples, the difference in thermal conductivity between that of the polymer and that of the thermal conductivity additive particles is +/- 10-20%, is at least +/- 100%, or is at least +/- 200% (two orders of magnitude).

[0038] Figure 4 illustrates a cross-section through an example end-use article 100. In this example, the article 100 includes an inner or innermost first radial layer 32a and an outer or intermediate second radial layer 34a. Although the article 100 may only have two such layers 32a/34a, as mentioned above, additional layers 32a/34a may be used. Here, the article 100 is shown with two layers 32a and two layers 34a configured in an alternating layer arrangement. Additional layers 32a/34a may also be used.

[0039] Figure 5 schematically illustrates another example article 200 and modification of the process 20. In this example, during the selective depositing of the first material 32, the selected depositing of the second material 34, or a combination thereof, an open space is left in order to form a continuous, open-ended passage 40. The passage 40 has a first open end 40a and a second open end 40b. For instance, the first open end 40a may be in a radially inner or innermost one of the layers and the second open end 40b may be in a radially outer or outermost one of the layers. Thus, the passage 40 may extend through at least one first radial layer 32a and through at least one second radial layer 34a. Alternatively, the passage 40 may extend through only one first radial layer 32a or only one second radial layer 34a. In use, the passage 40 may serve for cooling the article 200 by natural or active convective cooling, for example. In some cases, a coolant can be used, the coolant selected from air, liquid or a solid-containing liquid fluid.

[0040] Figure 6 illustrates another example article 300 and modification of the process 20. In this example, first and second radial layers 32a/34a are selectively deposited as described. However, during deposition of the first material, deposition of the second material, or combinations thereof, at least one open space is left to form of a controlled-geometry void 302. An electronic device 304 is then installed in the controlled-geometry void 302. For example, the controlled-geometry void 302 has a shape that corresponds to the shape of the electronic device 304. One or more subsequent layers 32a/34a are then deposited over and/or around the electronic device 304 such that the electronic device 304 becomes embedded in the alternating layer arrangement. Multiple electronic devices 304 can be incorporated into the article 300 using this technique. [0041] For example, the electronic device 304 can be, but is not limited to, a switch or a sensor for integrating additional functionality into the article 300. In further examples, the sensor or sensors can include Hall sensors, temperature sensors, motion detectors, accelerometers, chemical sensors and the like. In further examples, the electronic device 304 is a pre-existing device that is installed into the controlled-geometry void 302. However, in other examples, the electronic device 304 can be built or deposited in-situ in the controlled-geometry void 302 by way of electronics direct write or the like.

[0042] Although a combination of features is shown in the illustrated examples, not all of them need to be combined to realize the benefits of various embodiments of this disclosure. In other words, a system designed according to an embodiment of this disclosure will not necessarily include all of the features shown in any one of the Figures or all of the portions schematically shown in the Figures. Moreover, selected features of one example embodiment may be combined with selected features of other example embodiments.

[0043] The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.