WO2020091773A1

WO2020091773A1 - Sinterable setter with interface layer

Info

Publication number: WO2020091773A1
Application number: PCT/US2018/058585
Authority: WO
Inventors: James C. Mckinnell; Michael XU; John G. Liebeskind
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2018-10-31
Filing date: 2018-10-31
Publication date: 2020-05-07

Abstract

An example 3D fabrication method may include assembling a separately formed sinterable product and a separately formed coated sinterable setter coated with an interface layer in a supporting relationship with the coated sinterable setter supporting at least a portion of the sinterable product. The method may further include sintering the sinterable product and the coated sinterable setter while in the supporting relationship to form a sintered product and a sintered support setter. The interface layer at least substantially inhibits fusing of the sinterable product and the coated sinterable setter during sintering.

Description

SINTERABLE SETTER WITH INTERFACE LAYER

BACKGROUND

[0001] Three dimensional (3D) products are sometimes formed from sinterable materials, such as metallic powders. The sinterable materials, in particulate or powder form, may be bound together by a binder to form a sinterable product for densification in a sintering oven. During sintering, the sinterable product may sag or droop if not supported. Support setters are sometimes utilized to support the sinterable product during sintering.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Figure 1 is a flow diagram of an example 3D fabrication method.

[0003] Figure 2 is a diagram illustrating fabrication of a sintered product as part of an example 3D fabrication method.

[0004] Figure 3 is a is a sectional view schematically illustrating portions of an example 3D fabrication system during fabrication of an example sinterable setter.

[0005] Figure 4 is a sectional view schematically illustrating portions of an example material applicator of the system of Figure 3.

[0006] Figure 5 is a block diagram schematically illustrating portions of an example memory containing instructions for operation of the example system of Figure 3.

[0007] Figure 6 is a flow diagram of an example 3D fabrication method.

[0008] Figures 7A, 7B, 7C, 7D and 7E are side views illustrating an example fabrication of an example sintered three-dimensional product. [0009] Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements. The figures are not necessarily to scale, and the size of some parts may be exaggerated to more clearly illustrate the example shown. Moreover, the drawings provide examples and/or implementations consistent with the description; however, the description is not limited to the examples and/or implementations provided in the drawings.

DETAILED DESCRIPTION OF EXAMPLES

[00010] Disclosed herein are example 3D fabrication methods, 3D powder bed printed sinterable setters and 3D powder printed sinterable setter fabrication instructions that facilitate more economical and environmentally friendly fabrication of sinterable setters having an interface layer. In some implementations, the example 3D fabrication methods, 3D powder bed printed sinterable setters and 3D powder printed sinterable setter fabrication instructions further facilitate the fabrication of interface layer coated sinterable setters or live setters that may better mate with corresponding portions of a sinterable product during sintering to better support the sinterable product.

[00011] For purposes of this disclosure, the term“sinterable” when referring to material, a“sinterable product” or a“sinterable setter” refers to a material, product or setter having a general body or shape formed by build material or powder which is bound together by a binder agent or liquid, but where the particles of the powder or build material has not yet been fused or coalesced with one another. The term“sintered” when referring to a material, a“sintered product” or a“sintered support setter” refers to a material, product or setter having a general body or shape formed by a build material or powder in which the particles or particulates thereof have been heated to a sub solidus temperature such that the particles have coalesced with one another by solid state transport. Two additional types of sintering are commonly used depending on which materials are being sintered. Super-solidus sintering is a special case where sintering occurs a few degrees above the solidus temperature but below the liquidus temperature so a small percentage of the alloy liquifies, thereby enhancing transport and sintering. Liquid phase sintering occurs when a mixture of powders is used rather than a pre-alloyed powder. As the temperature is raised, a powder with a low melting point melts thereby enhancing transport. As the mixture of powders alloys together, the melting point increases and forms a solid through the duration of the sintering cycle. A few examples of commercial materials that use this technique are: dental amalgam Ag-Hg, Electrical contacts W-Cu, and Cu-Si.

[00012] “Live setters”, are setters that are formed from a sinterable build material that has similar, or the same, densification properties as compared to the sinterable build material forming the sinterable product itself. Because such live setters shrink or densify in proportion similar to the sinterable product being supported during sintering, such live setters may better support and maintain the geometry and shape of the supported product during sintering. Such live setters may be difficult to separate from the product following sintering.

[00013] The disclosed 3D fabrication methods, 3D fabrication systems and 3D powder printed sinterable setters provide such live setters with an interface layer on surfaces of the sinterable setter. The interface layer comprises materials that are less likely to coalesce at the temperatures reached during sintering. One example of such an interface material is a ceramic particulate material. Unfortunately, application of the interface layer, since it is through spraying or jetting, may result in the surrounding unused powder in the powder bed, powder which has not been bound by a binding agent, becoming contaminated with the interface layer material.

[00014] For purposes of this disclosure, the term“unused” or“leftover” when describing sinterable build material powder refers to portions of sinterable build material powder in a powder bed which was used to support and/or at least partially surround a sinterable product or a sinterable setter being fabricated, but which has not received any or a sufficient amount of binder agent to bind particles of the sinterable build material powder. In some fabrication processes, a very small portion of build material powder constituting the total volume of build material powder in a powder bed may be actually bound to form a sinterable product or sinterable setter. The remaining build material powder that is not bound and that does not form a sinterable product or a sinterable setter, or is not intermixed with an interface layer material, such as ceramic particles, to form an interface layer, is “unused”.

[00015] The disclosed example 3D fabrication methods, 3D powder bed printed sinterable setters and 3D powder printed sinterable setter fabrication instructions facilitate reuse or recycling of the“unused” powder. Because the application of the interface layer to the sinterable setter is isolated from unused powder, the unused build material powder is not contaminated with the interface layer material. As a result, the unused build material powder may be reused or recycled to form additional sinterable products or additional sinterable setters yet to be coated with an interface layer. In some implementations, the example3D fabrication methods, 3D powder bed printed sinterable setters and 3D powder printed sinterable setter fabrication instructions facilitate reuse or recycling of unused portions of the interface layer materials.

[00016] In some implementations, the sinterable setters and the sinterable products are both formed at the same time in a single volume of powder contained in a single powder bed. Following their fabrication, the sinterable setters and the sinterable products are removed from the powder bed. Thereafter, the sinterable setters have portions coated with an interface layer outside of the bed in which the setters were formed. Build material powder not used during the fabrication of the sinterable setters and sinterable products, the build material powder not bound by a binding agent during the fabrication of the sinterable setters in the sinterable products, remains within the powder bed for fabrication of additional sinterable setters and/or sinterable products or is removed from the powder bed and subsequently reloaded into the same or a different powder bed (and possibly supplemented with additional build material powder) to form additional sinterable setters and/or sinterable products.

[00017] In some implementations, the sinterable setters and the sinterable products may be formed in the same powder bed, but at different times. For example, a sinterable setter may first be formed and withdrawn from the powder bed followed by the forming of a sinterable product. In some implementations, the sinterable setters and the sinterable products may be formed in different powder beds. In either case, the sinterable setter is removed from the powder bed and then coated with the interface layer, away from any unused powder left over from its fabrication or any unused power left over from the fabrication of the sinterable product.

[00018] The disclosed example 3D fabrication methods, 3D powder bed printed sinterable setters and 3D powder printed sinterable setter further facilitate the fabrication of interface layer coated sinterable setters or live setters that may better mate with corresponding portions of a sinterable product during sintering to better support the sinterable product. Because the sinterable setter is coated or otherwise at least partially covered by the interface layer outside of the volume of build material powder used to form the sinterable setter, the characteristics of the interface layer, such as its thickness and density may be more precisely controlled. For example, in some implementations, the interface layer material may be applied to a sinterable setter after the sinterable setter has been removed from the build material powder used to form the sinterable setter. As a result, there is no build material powder to interfere or impact the concentration or thickness of the interface layer being formed. Because the interface layer may be more precisely controlled and its characteristics may be more reliably predicted, the 3D fabrication system forming the sinterable setter may better tune the geometry of the sinterable setter, taking into account the more reliable estimated thickness of the interface layer, such that the final interface layer coated sinterable setter better mates with and supports the sinterable product during sintering.

[00019] Disclosed herein is an example 3D fabrication method. The method may include assembling a separately formed sinterable product and a separately formed coated sinterable setter coated with an interface layer in a supporting relationship with the coated sinterable setter supporting at least portions of the sinterable product. The method may further include sintering the sinterable product and the coated sinterable setter while in the supporting relationship to form a sintered product and a sintered support setter. The interface layer at least substantially inhibits fusing of the sinterable product and the coated sinterable setter during sintering.

[00020] Disclosed is an example three-dimensional powder bed printed sinterable setter for assembly with a sinterable product. The sinterable setter may comprise a body of sinterable material shaped and sized to

dimensionally accommodate a subsequently applied interface layer so as to mate with the sinterable product with the interface layer during subsequent assembly with the sinterable product.

[00021] Disclosed is an example non-transitory computer-readable medium comprising instructions to direct the processor to receive a geometry of a final product and a characteristic of sinterable materials for three dimensional (3D) fabrication of the final product, instructions to direct the processor determine a geometry of a sinterable product formed from the sinterable materials to form the final product and instructions to direct the processor to determine a geometry of a sinterable setter to be formed by the sinterable materials. The geometry may be shaped and sized to dimensionally accommodate a subsequently applied interface layer so as to mate with and support the sinterable product with the interface layer upon assembly with the sinterable product.

[00022] Figure 1 is a flow diagram of an example method 20 for carrying out the fabrication of three-dimensional articles or products. Method 20 facilitates the fabrication and use of“live setters” and the provision of an interface layer on surfaces of the sinterable setter. Method 20 utilizes sinterable setters that are at least partially coated with an interface layer all being isolated from unused build material powder. In contrast to concurrently forming the sinterable setter, the sinterable product and the interface layer in a single powder volume in a single powder bed, the sinterable setter is separately coated with interface layer such that the unused powder left over from the fabrication of the sinterable setter is not contaminated and may be recycled or reused for fabricating additional sinterable products without weakening those sinterable products fabricated from the reused build material powder. Moreover, because the sinterable setters are at least partially coated with the interface layer outside of and away from the build material powder in a powder bed, more precise control over the thickness, composition and geometry of the interface layer may be achieved.

[00023] As indicated by block 22, at least portions of a sinterable setter are coated within interface material while the sinterable setter is isolated from unused build material powder. In other words, the sinterable setter is not coated with the interface material while the sinterable setter is in the same powder bed and partially supported by the same volume of powder that was used to fabricate the sinterable setter or the sinterable setter and the sinterable product. Where the sinterable setter is formed in a powder bed or is formed in the same volume of powder as the sinterable product, the sinterable setter is first removed from the powder and the powder bed prior to being coated with the interface layer. [00024] Prior to the coating of the sinterable setter, the sinterable product and the sinterable setter may be printed using the same bed or using different beds. After the sinterable product removal from the print bed, the sinterable setter is coated in a separate operation. Since the coating occurs in a different operation, the coating cannot contaminate the powder in the print bed. For example, the sinterable product and the sinterable setter may be formed in different powder beds at the same time or at different times. The processes used to form the sinterable product in the sinterable setter may be different or may be similar to one another. Alternatively, the sinterable product in the sinterable setter may be formed using the same powder bed, but at different times. In particular, one of the sinterable product and sinterable setter may be formed first and removed from the powder bed prior to forming of the other of the sinterable product and the sinterable setter in the same powder bed. The coating of the sinterable setter with an interface layer may occur as part of the process utilized to form the sinterable setter or may be carried out as a separate process in the same powder bed in which the sinterable setter was formed or at a location outside of the powder bed in which the sinterable setter was formed.

[00025] As indicated by block 24, the sinterable product and the sinterable setter coated with the interface layer are assembled in a supporting relationship with the coated sinterable setter supporting at least portions of the sinterable product. The sinterable product is a body of material that, upon being sintered, will form the final product, the end goal of the 3D printing process. In contrast, the sinterable setter may be a sacrificial component, a component that is merely used as part of the fabrication of the final product. The sinterable setter has a shape and size so as to support at least a portion of the sinterable product during sintering to inhibit drooping or sagging of the sinterable product during sintering.

[00026] The“supporting relationship” means that at least a portion of the sinterable product overlies the sinterable setter. The sinterable setter holds up the overlying portion of the sinterable product during sintering. In one implementation, the sinterable setter may include portions that extend vertically between portions of the sinterable product and the floor of the sintering oven during sintering. In one implementation, the sinterable setter may include portions that are vertically sandwiched between portions of the sinterable product, at least partially filling a gap or space between vertically spaced portions of the sinterable product to support the overlying portion of the sinterable product.

[00027] The assembly of the sinterable product and the sinterable setter in the supporting relationship may occur within a sintering oven or other sintering device. Alternatively, the assembly of the sinterable product and the sinterable setter may occur outside of the sintering oven or other sintering device, wherein the assembly is positioned into the sintering oven or sintering device. In one implementation, such assembly may be manually performed.

In yet other implementations, such assembly may be carried out with controlled robotic assembly mechanisms. The assembly of the live setter or setters and the sinterable product is then ready for sintering in an oven.

[00028] As indicated by block 248, the sinterable’s product and the coated sinterable setter, while in the supporting relationship, are sintered.

The heat applied by the sintering oven results in sintering of both the sinterable product and the sinterable setter to form a sintered product and a sintered support setter. In some implementations, the sinterable materials of the sinterable product and the sinterable setter constitute the same sinterable materials such that they densify or coalesce at substantially similar rates during sintering, maintaining their proportions to one another and the direct continuous physical contact between those portions of the sinterable setter initially assembled into contact with overlying portions of the sinterable product. In some implementations, the sinterable materials chosen for the sinterable product and the sinterable setter may be different, but have similar sintering densification properties (for example, within 10% of one another). [00029] As a follow-up process to method 20 described above, the sintered product and the now sintered support setter may be separated to yield the distinct final product, the sintered product. The interface layer previously coated or deposited upon at least those surfaces of the sinterable setter that contact and support the overlying portions of the sinterable product eases the task of separating the sintered product from the sintered support setter. In one implementation, the interface layer is a particulate material or granular material that coalesces or densifies at a higher temperature than the temperature at which the sinterable product in the sinterable setter densify or coalesce. In one example, the interface layer is a particulate material or granular material that coalesces or densifies at a temperature greater than the temperature at which the sintering oven during sintering. Because the interface layer is a particulate material or granular material, the particles of the interface layer are able to shift or move to accommodate size and shape changes of the sinterable product and the sinterable setter as they densify and undergo sintering. One example of such an interface layer comprises a granular or particulate layer of a ceramic material. In one implementation, the interface layer may comprise such a granular particular material adhered to the surface of the sinterable setter by an adhesive or binder material that decomposes, melts or otherwise changes state at the sintering temperatures such at the interface layer is shippable or movable during sintering. The binder material may be chosen so as to be easily washed away or removed from the finished sintered product following sintering.

[00030] Figure 2 is a diagram schematically illustrating the carrying out of method 20 described above with respect to Figure 1. As indicated by the box 50, a preformed sinterable setter 56 is at least partially coated with interface material 51 to form an interface layer 58 at least partially covering the sinterable setter 56. The sinterable setter 56 is not coated with the interface material 51 while the sinterable setter 56 is in the same powder bed and partially supported by the same volume of powder that was used to fabricate the sinterable setter 56 or the sinterable setter 56 and sinterable product 54. Where the sinterable setter 56 is formed in a powder bed or is formed in the same volume of powder as the sinterable product 54, the sinterable setter 56 is first removed from the powder and the powder bed prior to being coated with the interface layer 51.

[00031] As further shown by box 52, the sinterable product 54 and the coated sinterable setter 56 are assembled in a supporting relationship, wherein the sinterable setter 56 and its coating 58 underlie at least portions of the sinterable product 54. The assembly 60 is assembled outside of any surrounding loose particles or powder, forming a freestanding assembly ready for placement upon a shelf of the sintering oven for sintering.

[00032] In the example illustrated, sinterable setter 56 and interface coating 58 underlie an overlying portion 62 of sinterable product 54. The interface coating 58 directly contacts at least a portion of the overlying portion 62, the interface coating 58 being sandwiched between the overlying portion 62 and the sinterable setter 56. In the example illustrated, interface coating 58 further extends between side-by-side portions of the sinterable product 54 and the sinterable setter 56, isolating the sinterable setter 56 from the sinterable product 54. In some implementations, the interface coating 58 may completely surround or encapsulate the sinterable setter 56. In other implementations, the interface coating 58 may extend on selected exterior surface portions of the sinterable setter 56, those portions comprising portions that would otherwise directly contact exterior surfaces of the sinterable product 54. In one implementation, such assembly may occur in the sintering oven. In other implementations, the assembly may occur outside of the sintering oven, wherein the assemblies placed into the sintering oven.

[00033] As indicated by box 70, the assembly 60 undergoes sintering. During sintering, the sinterable product 54 and the sinterable setter 56 (shown in box 52) are exposed to temperatures above the sintering temperature of the material forming product 54 and setter 56 such that product 54 and setter 56 both density to form sintered product 74 and sintered support setter 76 (as shown in box 70). As noted above, in some implementations, the sinterable product 54 and the sinterable setter 56 are both formed from similar sinterable materials so they density or coalesce at similar rates and extents in response to similar temperature ranges. As noted above, the interface coating 58 comprises a granular particulate material, such as a ceramic particulate material, which does not sinter or does not coalesce and density during the sintering of the sinterable product 54 and the sinterable setter 56. In some implementations, the interface coating 58 may undergo some degree of coalescing or sintering, but to degrees insufficient to substantially impair the subsequent separation of the sintered product 74 and the sintered support setter 76.

[00034] As indicated by broken line box 80, the sintered product 74 is separated from the sintered support setter 76 and its interface layer coating 58. The interface layer 58 facilitates easier separation of the sintered product 74. Interface layer 58 may further facilitate easier cleaning and refinement of the final sintered product 74.

[00035] Figure 3 is a diagram schematically illustrating portions of an example sinterable setter fabrication system 120. System 120 may be used to fabricate an interface layer coated sinterable setter for use in supporting a separately fabricated sinterable product during sintering. System 120 fabricates a sinterable setter and separately coats the sinterable setter outside of the build material powder utilized to fabricate the sinterable setter to avoid contaminating the build material powder and to maintain more precise control over the characteristics of the interface layer. System 120 comprises powder bed 124, powder supply 126, binder applicator 128, interface applicator 130, interface material recovery/reuse system 132, interface material reservoir 134, input 136 and controller 140. Controller 140 contains processor 142 and memory 144. [00036] Powder bed 124 comprises a container having an interior for supporting and containing a mass of particulate material or powder 142. Powder supply 126 comprises a bin or container containing the powder 142 to be supplied to the interior of bed 124 and to replenish use powder. Examples of the powder or build material include, but are not limited to metal or metallic particulate material such as, SS316, SS316L, SS17-4PH, Ti6AI4V, Inconel, , or combinations thereof, wherein such materials are commercially available under the noted designations from GNK Sinter Materials at Auburn Hills, Michigan.

[00037] Binder applicator 128 comprises a source or reservoir of binder material and an associated applicator that selectively applies the binder material, such as a binder liquid, onto powder 142, wherein the binder material binds the powder together. In one implementation, binder applicator 128 applies a binder material selected such as a latex based ink. In one implementation, binder applicator 128 comprises at least one print bar that includes a multitude or an array of injection nozzles and that are selectively controlled and moved above the powder 142 in bed 124 to selectively applied the binder at precisely defined locations.

[00038] As shown by Figure 3, in one implementation, powder bed 142 is sized and binder applicator 128 is controlled so as to concurrently form both sinterable setter 164 and its corresponding sinterable product 165 in the same volume of powder 142 during a single 3D printing cycle. Sinterable product 165 corresponds to the sinterable setter 164 in that sinterable product 165 comprises cantilevered or undercut portions 167 that are to be to supported by the sinterable setter 164 one subsequent coated with an interface layer. In the example illustrated, setter 164 and product 165 are illustrated as being concurrently form the same layer of powder 142 such that the horizontally overlap one another within the volume of powder 142. In other

implementations, setter 164 and product 165 may be formed within the same volume 142, but in different horizontal layers of the volume of powder, layers that do not horizontally overlap one another. Once formed, both setter 164 and product 165 may be removed, wherein setter 164 is subsequently coated with an interface layer by interface applicator 130. In other implementations, setter 164 and product 165 may be formed in the same bed at different times/cycles or in completely different beds 124.

[00039] Interface applicator 130 comprises a source or reservoir of interface layer material and an associated applicator that selectively applies the interface material or interface layer material onto already the completed sinterable setter 164 after it has been removed from powder bed 124 and is supported by recovery/reuse system 132. The interface layer material comprises a powder or particulates of a material having a higher sintering temperature that of the powder or build material 142. Examples of the interface layer material include, but are not limited to ceramics such as zirconia, alumina, Ti02, BeO, BNCaO, Graphite, MgO, Mullite, SiC, and Si3N4 or combinations thereof. In one implementation, the interface layer material may be suspended or carried within a liquid, allowing it to be jetted as a liquid or in droplets onto sinterable setter 164, wherein the liquid carrier is subsequently evaporated or burnt off.

[00040] Figure 5 is a block diagram schematically illustrating an example interface applicator 130 that may be used to selectively apply interface layer 166 on sinterable setter 164. Interface applicator 130 comprises an individual nozzle or an array of nozzles 150. Nozzles 150 may be carried by print bar 151 that is controllably movable in a single dimension, two dimensions or three dimensions above the powder 142 in bed 124. Each of such nozzles 150 comprises a nozzle chamber 152, a nozzle orifice 154 and a fluid actuator 156.

[00041] Chamber 152 comprises a volume containing a volume of liquid carrying the interface layer material as in the case of interface applicator 130. Nozzle orifice 154 comprises an opening extending from chamber 152 through which the liquid is ejected.

[00042] Fluid actuator 156 comprises a mechanism that displaces fluid/liquid within chamber 152 to expel a stream or droplets of fluid through orifice 154 towards precise locations. In some examples, fluid action or 156 may comprise a heating element (e.g., a thermal resistor) that may be heated to cause a bubble to form in a fluid proximate the heating element. In such examples, a surface of a heating element (having a surface area) may be proximate to a surface of a fluid channel in which the heating element is disposed such that fluid in the fluid channel may thermally interact with the heating element. In some examples, the heating element may comprise a thermal resistor with at least one passivation layer disposed on a heating surface such that fluid to be heated may contact a topmost surface of the at least one passivation layer. Formation and subsequent collapse of such bubble may displace fluid within chamber 152 to expel fluid through orifice 154. The fluid or liquid carrying the interface materials or particles and jetted onto the previously bound powder build material is subsequently burnt off or evaporated during sintering or prior to sintering.

[00043] In other examples, the fluid actuator 156 may comprise a piezo membrane based actuator, and electrostatic membrane actuator, a mechanical/impact driven membrane actuator, a magnetostrictive drive actuator, an electrochemical actuator, in external laser actuator (that form a bubble through boiling with a laser beam), other such microdevices, or any combination thereof. In some implementations, the fluid actuators may displace fluid through movement of a membrane (such as a piezo-electric membrane) that generates compressive and tensile fluid displacements to thereby cause inertial fluid flow. In one implementation, binder applicator 128 may have the same construction as interface applicator 130, wherein the binder applicator 130 may also include a nozzle or an array of nozzles carried by controllably positionable print bar to selectively deposit a binder agent to the powder 142 in bed 124.

[00044] In one implementation, interface applicator 130 may comprise other devices for applying interface layer materials to those external surfaces of sinterable setter 164 that are to subsequently come into direct physical contact with portions of the sinterable product following assembly and during sintering. For example, interface layer 166 may be sprayed, brushed or otherwise deposited manually or in an automated fashion over selected outer surface portions of sinterable setter 164.

[00045] Platform/interface material recovery/reuse system 132 comprises a platform for supporting the sintered support setter 164 outside of powder bed 124 during the application of interface layer materials by interface applicator 130. In one implementation, system 132 comprises a trough, reservoir, pan or other basin or container underlying a screen that captures interface layer materials (and the liquid carrier in some implementations) that have been output by applicator 130, but not deposited upon or adhered to sinterable setter 164 to form interface layer 166. Recovery/reuse system 132 facilitates a collection of unapplied portions of the interface layer materials for disposal or reuse. In some implementations, as indicated by broken lines, system 120 additionally comprise the interface material reservoir 134, wherein the interface layer materials recovered by system 132 are recycled by being supplied to interface material reservoir 134 for subsequent reapplication by interface applicator 130 to the same sinterable setter 164 or to a subsequently formed sinterable setters 164 position on the platform of system 132.

[00046] Input 136 comprises an interface by which a user or person may enter commands and input information to system 120. Input 136 may comprise a network connection or storage media which provides files, commands and other data, a touchpad, a touch screen, a keyboard, a mouse, a stylus, a microphone which speech recognition software capabilities and the like. Input 136 may be utilized to input geometries of the final product which is to be formed using the sinterable setter and coating to be fabricated by system 120. Input 136 may be utilized to input geometries of a sinterable product which is to be supported by the coated sinterable setter that is to be formed by system 120. Input 136 may be used to input characteristics of the powder build material, characteristics of the binder and/or characteristics of the interface layer material. Input 136 may further be used to input a selected thickness of the interface layer depending upon the persons objective of facilitating subsequent separation of the sintered product from the sintered support setter.

[00047] Controller 140 comprises a processor 142 and associated non- transitory computer-readable medium or memory 144 for controlling system 120. Memory 144 comprises a non-transitory computer-readable medium containing instructions for directing the processor 142 to prompt for input of data or commands, to analyze such input data and commands, to receive sensed feedback from system 120 and analyze such feedback, and to output control signals controlling the operation of powder supply 126, binder applicator 128 and interface applicator 130. Controller 140 may precisely control the fabrication of a sinterable setter based upon characteristics of the sinterable product, the interface layer and the materials thereof.

[00048] Figure 5 is a block diagram illustrating an example non- transitory computer-readable medium or memory 244 which may be utilized as part of system 120 for directing processor 142 in the fabrication of sinterable setters and the coating of such sinterable setters with an interface layer. Memory 244 comprises final product geometry input instructions 246, sinterable product geometry instructions 248 and sinterable setter geometry instructions 250.

[00049] Instructions 246 direct a processor 142 to receive a geometry of the final product and characteristics of the sinterable materials that are be used to form the three-dimensional fabrication of the final product. In one implementation, instructions 246 may direct the processor 142 to prompt for such input via input 136. In other implementations, instructions 246 may retrieve the geometries from a database or other source for the geometries of the final product. The characteristics of the sinterable materials may involve an indication of a type or name for a classification of sinterable materials or may comprise actual densification or centering properties of the sinterable material. Such characterization may be input or may be retrieved from a database.

[00050] Instructions 248 to determine a geometry of a sinterable product to be formed from the sinterable materials so as to form the final product, the dimensions of which were provided or retrieved per instructions 246. In one implementation, structure 248 directs the processor 142 in determining, based upon the characteristics of the sinterable materials, the degree or extent of densification to be expected during sintering of the sinterable product, oversizing the sinterable product such that sintering of the sinterable product will yield the geometries of the final product as received per instructions 246.

[00051] Instructions 250 direct a processor 142 to determine a geometry of the sinterable setter to be formed by the sinterable materials, wherein the geometry of the sinterable setter is shaped and size to dimensionally accommodate a subsequently applied interface layer so as to mate with and support the sinterable product with the interface layer upon assembly with the sinterable product. As such, instructions 250 take into account the shrinking and densification of the sinterable product, the shrinking and densification of the sinterable setter, the non-densification, non-shrinking of the interface layer, the thickness of the interface layer and the supporting relationship of the assembly in determining the geometry of the sinterable setter prior to being coated with the interface layer. The final geometry (shape and size) of the sinterable setter is then utilized by controller 140 to output control signals to binder applicator 128 and interface applicant 130 in the forming of the sinterable setter.

[00052] Figure 6 is a flow diagram of an example 3D fabrication method 400. Method 400 may be used to fabricate and interface layer coated sinterable setter for use in supporting a sinterable product during sintering. Method 400 separately coats the sinterable setter outside of a powder bed to reduce the possibility of unused portions of build material becoming contaminated with the interface layer materials that might otherwise occur with concurrent fabrication of both the sinterable setter, its interface coating and the sinterable product in a single batch or in a single process in a single powder bed. Because method 400 applies the interface layer to the sinterable setters outside of the powder bed and it’s powder, more precise control over the thickness and geometry of the interface layer may be achieved. Although method 400 is described in the context of being carried out by system 120, method 400 may likewise be carried out with system 20 or with other similar systems.

[00053] As indicated by block 404, system 120 obtains the part form geometry, the geometry of the final three-dimensional product to be fabricated. In some implementations, system 120 may alternatively obtain the geometry of the sinterable product which is to form the final product. The geometry may be obtained by retrieving such data from a database or by prompting a user to directly input sent information through input 136.

[00054] In one implementation, as part of obtaining the geometry of the sinterable product, system 120 obtains characteristics of the part grade powder build material, the characteristics of powder 142. Such characteristics may be in the form of the densification properties of the powder 142 or an identifier of the material of powder 142, wherein the particular properties are retrieved from a database or other source using the identification of the powder 142. [00055] As indicated by block 406, controller 140 supplies the powder build material to bed 124 and a layer by layer fashion. As indicated by block 408, based upon the geometry (size and shape) of the“green part form”, the sinterable product, as directly received in block 404 or as determined based upon the geometry of the final product received in block 404, controller 140 outputs control signals controlling the deposition of binder by binder applicator 128 to each sequentially formed layer of powder build material to form the sinterable product. In the example illustrated, binder applicator 128 is similar to that shown in Figure 4, wherein applicator 128 jets the binder onto the powder 142. Once completed, as indicated by block 410, the sinterable product (the“green part form”) is“depowdered” in that it is removed from the powder bed or the unused powder surrounding the sintered product is removed.

[00056] As indicated by block 414, controller 140 of system 320 obtains the geometry of the sinterable setter. In one implementation, this geometry is retrieved from a database or directly supplied via input 136. In one implementation, controller 140 follows instructions contained in memory 244 (described above) to determine the geometry of the body of the sinterable setter to dimensionally accommodate a subsequently applied interface layer so as to facilitate mating with the sinterable product produced following block 408 with the subsequently coded body of the sinterable setter.

[00057] As indicated by block 416, controls powder supply 126 to deposit the powder build material in a layer-by-layer fashion into bed 124 as the uncoated body sinterable setter is formed. The powder build material may be a setter-grade build material or a better grade powder build material. A setter grade powder build material may include contaminants or otherwise have a lower quality, less structural strength following sintering, as the setter is to merely function as a support for the sinterable product during sintering.

As indicated by block 418, based upon the geometry (size and shape) of the sinterable setter (“live setter), as directly received in block 404 or as determined based upon the geometry of the final product received in block 414 or determined following the instructions in memory 244, controller 140 outputs control signals controlling the deposition of binder by binder applicator 128 to each sequentially formed layer of powder build material to form the uncoated sinterable setter. In the example illustrated, binder applicator 128 is similar to that shown in Figure 4, wherein applicator 128 jets the binder onto the powder 142. Once completed, as indicated by block 420, the sinterable setter (the“setter part form”) is depowdered in that the sinterable setter is removed from the powder bed or the unused powder surrounding the sinterable support setter is removed.

[00058] As indicated by block 422, an interface material is coated or layered on exterior surfaces of the previously uncoated sinterable setter. In one implementation, the interface layer material is applied by interface applicator 130 described above. In one implementation, the interface layer is controllably applied to those external surfaces of the body of the sinterable setter that are to subsequently come into direct physical contact with portions of the sintered product following assembly and during sintering. In yet other implementations, the interface layer may be applied in other manners. For example, the interface layer may be sprayed, brushed or otherwise deposited manually or in an automated fashion over selected outer surface portions of the uncoated body of the sinterable setter.

[00059] As indicated by block 424, the sinterable product and the sinterable setter are assembled in a supporting relationship with one another, wherein portions of the sinterable setter underlie portions of the sinterable product. As indicated by block 426, the assembly is sintered in a sintering oven. As indicated by block 428, following sintering, the sintered product is separated from the sintered support setter and other sintered support setters that may also have been used to support portions of the sinterable product during sintering. [00060] Figures 7A-7E illustrate an example 3D fabrication method 500 which follows or similar to methods 20 and 400 described above. As shown by Figure 7A, an example sinterable product 502 is formed. Product 502 is three-dimensional and comprises elevated and unsupported surfaces 504-1 , 504-2 (collectively referred to as surfaces 504). It should be appreciated that the particular geometry shown in Figure 10 may have a variety of other sizes and shapes it is merely an example.

[00061] As shown by Figure 7B, a pair of coated sinterable setters 508-1 and 508-2 are formed. Uncoated sinterable support bodies 510-1 and 510-2 (collectively referred to as bodies 510) are initially formed and then coated with interface layers 512-1 and 512-2 (collectively referred to as layers 512), respectively. In one implementation, the uncoated sinterable support bodies 510 may be formed in a powder bed as described above. In the example illustrated, layers 512 are formed by an interface layer applicator 530 spraying and interface layer material 531 onto exterior surfaces of bodies 510. In other implementations, the interface layer material 531 may be deposited or coated upon bodies 510 by being jetted, brushed or otherwise applied to the exterior surfaces of bodies 510.

[00062] As shown by Figure 7C, the separately formed sinterable product 502 and the coated sinterable setters 508 are assembled in a supporting relationship. In the example illustrated, the coated sinterable setter 508-1 is assembled so as to underlie surface 504-1 so as to support surface 504-1 above a floor 513 of a sintering oven. In the assembled state, interface layer 512-1 to directly contacts the overlying surface 504-1.

Similarly, the coated sinterable setter 508-2 is assembled so as to underlie surface 504-2 so as to support surface 504-2 above floor 513 the sintering oven. In the assembled state, interface layer 512-2 directly contacts the overlying surface 504-2. [00063] As shown by Figure 7D, the assembly of the sinterable product 502 and the multiple sinterable setters 508 undergo sintering to form sintered product 520 and sintered support setters 522-1 , 522-2 (collectively referred to as supports 522). The interface layers 512 do not undergo sintering or fusing, maintaining their particulate or granular nature. During such sintering, the sinterable materials or powder build materials of both sinterable product 502 and sinterable setters 508 undergo densification and/or coalescing at substantially similar or the same rates such that setters 508 remaining continuous supporting contact with surfaces 504-1 and 504-2. As a result, sag or droop is minimized or avoided and the intended geometry of the final sintered product is achieved. As shown by Figure 7E, the final sintered product 520 is separated from the sintered supports 522. Because the interface layers 512 do not coalesce or fuse during this the above sintering, layers 512 further assist in separation of sintered product 520.

[00064] Although the present disclosure has been described with reference to example implementations, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the claimed subject matter. For example, although different example implementations may have been described as including features providing one or more benefits, it is contemplated that the described features may be interchanged with one another or alternatively be combined with one another in the described example implementations or in other alternative implementations. Because the technology of the present disclosure is relatively complex, not all changes in the technology are foreseeable. The present disclosure described with reference to the example implementations and set forth in the following claims is manifestly intended to be as broad as possible. For example, unless specifically otherwise noted, the claims reciting a single particular element also encompass a plurality of such particular elements. The terms“first”,“second”,“third” and so on in the claims merely distinguish different elements and, unless otherwise stated, are not to be specifically associated with a particular order or particular numbering of elements in the disclosure.

Claims

WHAT IS CLAIMED IS:

1. A three-dimensional (3D) fabrication method comprising:

coating at least portions of a sinterable setter with interface material while the sinterable setter is isolated from unused build material powder;

assembling a sinterable product and the sinterable setter coated with the interface layer in a supporting relationship; and

sintering the sinterable product and the coated sinterable setter while in the supporting relationship.

2. The fabrication method of claim 1 further comprising: forming the sinterable setter separate and independently of the sinterable product, wherein the sinterable setter is formed in a separate process than that of the sinterable product; and coating a support region of the sinterable setter with the interface layer.

3. The fabrication method of claim 2, wherein coating the sinterable setter with the interface layer comprises jetting a ceramic material through a nozzle with an electrically controlled fluid actuator.

4. The fabrication method of claim 2, wherein the sinterable setter is formed in a first powder bed and wherein the sinterable product is formed in a second powder bed.

5. The fabrication method of claim 2, wherein the sinterable setter is formed in a powder bed, wherein the sinterable product is formed in the powder bed concurrently with the sinterable setter and wherein the sinterable setter is coated with the interface layer outside the powder bed.

6. The fabrication method of claim 1 , wherein the interface layer comprises a ceramic material.

7. The fabrication method of claim 1 , wherein interface layer comprises particles selected from a group of particles consisting of at least one of the Zirconia, Alumina, T1O2, BeO, BNCaO, Graphite, MgO, Mullite, SiC, and Si₃N_4. 8. The fabrication method of claim 1 , wherein the sinterable product and the coated sinterable setter are formed from a same material. 9. The fabrication method of claim 1 further comprising: recovering the interface material that has been directed towards the sinterable setter but not adhered to the sinterable setter; and applying the recovered interface material to a second sinterable setter to form an interface layer at least partially over the sinterable setter. 10. The fabrication method of claim 1 further comprising: assembling the separately formed sinterable product and a second sinterable setter coated with a second interface layer in a supporting relationship with the second coated sinterable setter supporting the sinterable product; and sintering the sinterable product while the sinterable product is supported by both the coated sinterable setter and the second coated sinterable setter. i 11. A three-dimensional powder bed printed sinterable setter for

2 assembly with a sinterable product, the sinterable setter comprising:

3 a body of sinterable material shaped and sized to

4 dimensionally accommodate a subsequently applied

5 interface layer so as to mate with the sinterable product with

6 the interface layer during subsequent assembly with the

7 sinterable product.

1 12. The three-dimensional powder bed printed sinterable setter of claim

2 11 , wherein the sinterable material comprises a ceramic.

1 13. The three-dimensional powder bed printed sinterable setter of claim

2 1 further comprising the interface layer.

1 14. A non-transitory computer-readable medium comprising:

2 instructions to direct the processor to receive a geometry of

3 a final product and a characteristic of sinterable materials for three

4 dimensional (3D) fabrication of the final product;

5 instructions to direct the processor determine a geometry of

6 a sinterable product formed from the sinterable materials to form

7 the final product; and

8 instructions to direct the processor to determine a geometry

9 of a sinterable setter to be formed by the sinterable materials, the0 geometry being shaped and sized to dimensionally accommodate a1 subsequently applied interface layer so as to mate with and support2 the sinterable product with the interface layer upon assembly with3 the sinterable product. i 15. The non-transitory computer-readable medium of claim 14 further

2 comprising instructions to direct a processor to output control signals to direct a

3 fluid actuator to selectively eject an interface material onto the sinterable setter

4 based upon the determined geometry of the sinterable product.