WO2020091774A1

WO2020091774A1 - 3d powder sinterable setters

Info

Publication number: WO2020091774A1
Application number: PCT/US2018/058587
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

A three-dimensional (3D) fabrication method may include fabricating a first sinterable product in a first volume of powder, fabricating a second sinterable product from unused portions of the powder of the first volume, fabricating a first sinterable setter to support the first sinterable product in a second volume of powder, coating the first sinterable setter with an interface layer while the sinterable setter is within the second volume of powder and fabricating a second sinterable setter from unused portions of the powder of the second volume. The second sinterable setter is coated with an interface layer.

Description

85017738

3D POWDER SINTERABLE SETTERS

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. Setters are sometimes utilized to support the sinterable product during sintering. To facilitate separation of the final sintered product from its setter or setters, the setters are sometimes provided with an interface layer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Figure 1 is a flow diagram of portions of an example 3D fabrication method for fabricating sinterable products and coated sinterable setters.

[0003] Figure 2 is a diagram illustrating various fabrication stages for the fabrication of multiple sinterable products and multiple sinterable setters,.

[0004] Figure 3A is a schematic diagram of an example 3D fabrication system during the fabrication of a first sinterable setter.

[0005] Figure 3B is a schematic diagram of the example 3D fabrication system of Figure 3A during the fabrication of a second sinterable setter.

[0006] Figure 4 is a sectional view schematically illustrating portions of an example fluid ejector of the example 3D fabrication system of Figure 3A.

[0007] Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements. The figures are not 85017738

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

[0008] Disclosed herein are example 3D fabrication methods, 3D fabrication systems and 3D powder sinterable setters that provide for more economical and environmentally friendly fabrication of powder sinterable setters having an interface layer.

[0009] 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 85017738

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-Su.

[00010] “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.

[00011] 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, with powder-based 3D printing systems, application of the interface layer, since it is through spraying or jetting, may result in the surrounding leftover powder in the powder bed, powder which has not been bound by a binding agent, becoming contaminated with the interface layer material.

[00012] Rather than disposing of the leftover powder that has become contaminated, the example 3D fabrication methods, 3D fabrication systems and 3D powder sinterable setters reuse or recycle the potentially contaminated powder. The example 3D fabrication methods, 3D fabrication systems and 3D powder sinterable setters facilitate the fabrication of 3D powder sinterable setters using leftover or recycled powder that may have been contaminated with interface layer materials during the prior fabrication 85017738

of an interface layer coated 3D sinterable setter. The example 3D fabrication methods and 3D fabrication systems substantially isolate the potentially contaminated powder that is being reused for the fabrication of setters from the uncontaminated powder used to fabricate the sinterable product itself so as to maintain the quality of the sinterable product and the final 3D product.

[00013] For purposes of this disclosure, the term“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“leftover”.

[00014] Disclosed herein is an example three-dimensional (3D) fabrication method that may include fabricating, in a first volume of powder, a first sinterable setter to support a sinterable product, coating the first sinterable setter with a first interface layer while the first sinterable setter is within the first volume of powder, fabricating a second sinterable setter in a second volume of powder at least partially comprising leftover portions of the powder of the first volume and coating the second sinterable setter with a second interface layer while the second sinterable setter is within the second volume of powder.. 85017738

[00015] Disclosed herein is an example three-dimensional (3D) fabrication system. The system may include a powder bed, a binder applicator to selectively apply binder to powder within the powder bed to form a sinterable product, an interface layer applicator to selectively apply an interface material to bound powder within the powder bed to form a sinterable setter, a first powder bin, a second powder bin, a first powder passage from the powder bed to the first powder bin, a second powder passage from the powder bed to the second powder bin, a powder transfer system and a controller. The powder transfer system is: (1) to move leftover powder in the powder bed to the first powder bin following the forming of the sinterable setter in the powder bed and (2) to supply leftover powder from the second powder bin to the powder bed prior to forming of a second sinterable setter in the powder bed. The controller is to output control signals causing the powder transfer system to move the leftover powder in the powder bed to the first powder bin following the forming of the first sinterable setter in the powder bed and to output control signals causing the powder transfer system to move leftover powder from the first powder bin and the second powder bin to the powder bed to form a volume of powder for forming the second sinterable setter.

[00016] Disclosed herein is an example three-dimensional (3D) powder sinterable setter. The setter may include a main body comprising a powder comprising sinterable particulates interspersed throughout the main body, interface material particulates interspersed throughout the main body and amongst the sinterable particulates and a binder binding the sinterable particulates and the interface material particulates to form the main body. The setter may additionally include a layer of the interface material extending over the main body.

[00017] Figure 1 is a flow diagram illustrating 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 85017738

provision of an interface layer on surfaces of the sinterable setter. Rather than disposing of the unused powder that has become contaminated, method 20 reuses or recycles the potentially contaminated powder.

Method 20 facilitates the fabrication of 3D powder sinterable setters using unused or recycled powder that may have been contaminated with interface layer materials during the prior fabrication of an interface layer coated 3D sinterable setter. At the same time, method 20 isolates the potentially contaminated powder that is being reused for the fabrication of setters from the uncontaminated powder used to fabricate the sinterable product itself so as to maintain the quality of the sinterable product and the final 3D product.

[00018] As indicated by block 24, the first sinterable product is fabricated in a first volume of powder. The powder comprises a mass of sinterable particulate build material. 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. In one implementation, the sinterable product is fabricated with an additive manufacturing process wherein a binder agent or liquid is patterned across a topmost layer of the powder in a powder bed. A new layer of powder is formed over top of the prior layer to which the binder agent was applied. The binder agent or liquid is then patterned across this new layer. This process is repeated as the binder bound portions of each layer of powder are effectively stacked upon one another to collectively form a three- dimensional product.

[00019] In some implementations, the binder agent is further solidified or cured. Such solidification or curing may occur layer by layer after the binder agent is applied, may occur after a set of multiple layers of powder with their bound portions have been completed, or after all of the layers of 85017738

bound powder forming the three-dimensional sinterable product have been completed. In one implementation, such curing of the binder agent or agents may be achieved by applying ultraviolet light or heat to the binding agent as applied to selected portions of the powder layer, depending upon the nature the binder agent being used. For example, in one

implementation, the binder agent may comprise a latex ink. based binder agent that is thermally cured to bind the powder build material particles together. Following the application of the binder, and possible curing, the resulting first sinterable product is removed from the remaining unused, unbound build material powder in the powder bed.

[00020] As indicated by block 26, the unused portions of the sinterable build material powder, the remaining portions of powder from the fabrication of the first sinterable product, are used to fabricate a second sinterable product. In one implementation, the unused portions of the sinterable build material powder from the fabrication the first sinterable product may be removed from the powder bed and redeposited in the powder bed or a different powder bed for the fabrication of the second sinterable product. The process used to fabricate the second sinterable product may be substantially identical to the process used to fabricate the first sinterable product.

[00021] As indicated by block 28, a first sinterable setter is fabricated in a second volume of build material powder for supporting the first sinterable product. The second volume of build material power may be at least partially composed of unused portions of the sinterable build material powder left over from the fabrication of the first sinterable product or left over from the fabrication of the second sinterable product. As such, the second volume of build material powder is composed of sinterable particulate material substantially identical in composition to that of the build material powder of the first volume. In other implementations, the second volume of build material powder may be composed of a sinterable 85017738

particulate material that is different from the build material powder of the first volume. In one implementation, the build material powder of the second volume has densification or sintering properties similar to those properties of the build material powder of the first volume such that the resulting sinterable setter may constitute a“live” setter, proportionally coalescing and densifying with the coalescing and densifying of the sinterable product during sintering to better maintain the targeted geometry of the sintered product, the final three-dimensional product being fabricated.

[00022] In one implementation, the first sinterable setter may be fabricated using a process substantially similar to or the same as the process used to form or fabricate the first sinterable product or the second sinterable product, wherein a binding agent or binding liquid is selectively and controllably applied to a layer of powder build material and wherein this process is repeated layer by layer until the stack of bound powder build material collectively form a three-dimensional sinterable setter.

[00023] As indicated by block 30, the first sinterable setter being formed within the powder bed in the second volume of build material powder is coated with an interface layer. In one implementation, during the application of the binder agent to each individual layer, portions of the interface layer are deposited alongside the exterior surface of the binder agent bound build material powder. For example, application of the binder agent to a first layer of the build material powder may form regions of bound build material powder in the layer of otherwise unbound powder. Before depositing another layer of build material over the first layer, interface layer material, such as ceramic particulate, is sprayed, jetted or otherwise deposited along the perimeter of the regions. In one

implementation, the interface layer material is absorbed or dispersed into the spaces or interparticle gaps between the individual build material particles of the powder. In other words, just as the liquid binder agent is 85017738

absorbed into spaces between the particles of the build material powder, the interface layer material particles (carried by a liquid carrier or solvent) are absorbed into spaces between the particles of the build material powder, alongside a perimeter those binder bound regions of the build material powder. The concentration of the interface layer material absorbed into the first layer adjacent the bound regions of the first layer is sufficiently high so as to reduce or inhibit densification or coalescing of the build material powder in which the interface layer material particles have been dispersed during subsequent sintering. In some implementations, the interface layer material may be directly deposited on top of the first layer prior to the second layer of build material powder being deposited over the first layer. In some implementations, multiple interface layers are sequentially deposited to facilitate separation of the setter and the product. In some implementations, at least two layers of interface material are applied. In yet other implementations, 4 to 6 layers of interface material are applied to make the breakaway easier.

[00024] Thereafter, the next second layer of powder is laid over the first layer, the binder agent is applied to the second layer to bind selected portions of the second layer, stacked with respect to the bound portions of the first layer, and the interface layer material is sprayed, jetted or otherwise deposited along the bound regions of the second layer and/or on top of the second layer. In some implementations, interface layer material may be separated deposited to form upright structures extending from a top of an underlying layer of build material powder, bound or unbound, wherein the next successively applied layer of build material powder fills in and extends along the side surfaces of the upright structures.

[00025] During the formation of the interface layer adjacent to exterior surface portions of the sinterable setter, the interface layer materials may diverge from their intended target locations. For example, spraying of the interface layer materials may result in portions of the spray diverging onto 85017738

other portions unbound portions of the build material powder in the powder bed. This may result in droplets or small agglomerations of the interface layer materials being spread across unused portions of the build material powder. As a result, such unused portions of the build material powder may become contaminated with the interface layer material. Use of the contaminated build material powder when fabricating a sinterable product may result in the final sintered product having lower structural integrity or strength. However, as the main purpose of the sinterable setter is simply to support the sinterable product and prevented from saying or drooping during sintering, the contaminated build material powder may be well-suited for fabricating additional sinterable setters.

[00026] As indicated by block 32, method 20 takes advantage of the recognition that the contaminated build material power may be well suited for fabricating sinterable setters. As indicated by block 32, a second sinterable setter is fabricated from the unused portions of the powder of the second volume, those portions of the build material powder which may have been contaminated with the interface materials used to coat the first sinterable setter within interface layer. The second sinterable setter may be fabricated in a process substantially similar to or the same as the process utilized to fabricate the first sinterable setter, but for the recycle use of the particulate build material powder that has been contaminated with interface layer materials.

[00027] As indicated by block 34, a second interface layer is formed on the second sinterable setter while the second sinterable setter is within the second volume of powder, powder having interspersed throughout interface layer materials. Once the second sinterable setter has been completed with its coating of an interface layer, the coated sinterable setter is removed from the second volume of powder. Because the second sinterable setter was formed in a volume of powder composed of powder contaminated with 85017738

interface layer materials, the body of the second sinterable setter also includes interface layer materials interspersed throughout.

[00028] In one implementation, the method 20 may be carried out in a single powder bed as follows: 1) start with a clean printer. 2) load clean powder into the printer powder supply (such as a piston at the low part of its stroke). 3) lower build piston by one layer thickness. 4) raise supply piston slightly more than build piston was lowered. 5) With a roller or blade, transfer the powder from the supply piston to the build piston. The powder is spread in a uniform layer on the build piston. 6) print binder into the powder where needed to make a part or parts. 7) repeat steps 3-6 until entire part or parts are printed. 8 remove parts and clean powder from the printer. 8) load contaminated or clean powder into the printer’s powder supply (such as a piston at the low part of its stroke). 9) lower build piston by one layer thickness. 10) raise supply piston slightly more than build piston was lowered. 11 ) With a roller or blade, transfer the powder from the supply piston to the build piston. The powder is spread in a uniform layer on the build piston. 12) print binder and interface material into the powder where needed to make a coated setter or coated setters. 13) repeat steps 9-12 until entire part or parts are printed. 14) remove coated setter, coated setters and contaminated powder from the printer. 15) clean printer. With two printers, one printer could be printing parts with clean powder and the other printer could be printing setters.

[00029] Figure 2 is a diagram illustrating various fabrication stages for the fabrication of multiple sinterable products and multiple sinterable setters, partially utilizing method 20 described above. As indicated by fabrication stage 124, a first sinterable product 200 is fabricated in a first volume 202 of a build material powder, a mass of sinterable particles. As described above with respect to block 24, the powder may comprise a mass of sinterable particulate build material. Examples of the powder or build material include, but are not limited to metal or metallic particulate 85017738

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. In one implementation, the sinterable product is fabricated with an additive manufacturing process wherein a binder agent or liquid is patterned across a topmost layer of the powder in a powder bed. A new layer of powder is formed over top of the prior layer to which the binder agent was applied. The binder agent or liquid is then patterned across this new layer. This process is repeated as the binder bound portions of each layer of powder are effectively stacked upon one another to collectively form a three-dimensional product.

[00030] In some implementations, the binder agent is further solidified or cured. Such solidification or curing may occur layer by layer after the binder agent is applied, may occur after a set of multiple layers of powder with their bound portions have been completed, or after all of the layers of bound powder forming the three-dimensional sinterable product have been completed. In one implementation, such curing of the binder agent or agents may be achieved by applying ultraviolet light or heat to the binding agent as applied to selected portions of the powder layer, depending upon the nature the binder agent being used. For example, in one

implementation, the binder agent may comprise a latex ink based binder agent that is thermally cured to bind the powder build material particles together. Following the application of the binder, and possible curing, the resulting first sinterable product is removed from the remaining leftover, unbound build material powder in the powder bed.

[00031] As shown by fabrication stage 124, the example sinterable product 200 is three-dimensional and comprises an internally extending cavity 204 which may otherwise result in portions of product 200 dragging or drooping into the cavity during sintering, depending upon the orientation of the sinterable product 200 during sintering. For example, when sintered 85017738

in the orientation shown in Figure 2, portion 206 may droop downwardly. When sintered in the orientation shown Figure 2, but inverted, portions 208 may droop or sag inwardly. When sintered in an orientation 90° rotated from that shown in Figure 2, portion 206 or one of portion 208 may sag or droop into the cavity 204 during sintering. Although the sinterable product is illustrated as having an inverted U-shaped cross-sectional shape, in other implementations, the example sinterable product may have other shapes. For example, the example sinterable product 206 may have a cantilevered portion that, unless supported by sinterable setter, may sag or droop during sintering.

[00032] As shown by stage 126, and described above with respect to block 26, a second sinterable product 210 is fabricated from and using the leftover portions of the build material powder of the first volume 202.

Although product 210 is illustrated as having the same size and shape as product 200, in other implementations, product 210 may have a different size and/or shape as compared to product 200. As indicated by arrow 213, the leftover portions of volume 202 form at least a part of the volume 212 of build material powder utilized to form sinterable product 210. In some implementations, the reused portions of volume 202 may be sufficient to form the entire volume 212, all of the sequentially formed layers of build material powder that are stacked upon one another and which have selected portions bound by a binder agent to form sinterable product 210.

[00033] In other implementations, the build material powder being reused from volume 202 may be supplemented with previous the leftover build material powder. For example, the fabrication of sinterable product 200 and stage 124 may consume 20% of the total volume 202 of build material powder. In circumstances where the sinterable product 210 is the same as the sinterable product 200, volume 212 may be supplemented so as to replace the 20% of the volume 202 that was consumed such that volume 212 is the same as volume 202. In other implementations, the 85017738

sinterable product 210 may be smaller than that of sinterable product 200 or may have a geometry (size and/or shape) that demands a smaller volume of build material powder for its fabrication. In some

implementations, the entire volume 212 used to form product 210 may be satisfied with the recycled or leftover portion of volume 202 from the fabrication of sinterable support 200. In still other implementations, the sinterable product 210 may be larger than the sinterable product 206 or may have a geometry that demands larger volume 212 of build material powder. In such circumstances, the portions of the leftover volume 202 of build material powder may be supplemented with additional build material powder to satisfy the build material powder demands for the fabrication of sinterable product 210.

[00034] As shown by stage 128 and described with respect to block 28, a first sinterable setter 220 is fabricated in a second volume 222 of build material powder. In one implementation, the second volume 222 of build material powder may comprise the same build material powder composition as that of volumes 202 or 212 described above. In some implementations, the build material powder forming volume 222 may be at least partially composed of leftover portions of the build material powder from volumes 202 or 212, portions of the build material powder that forms volumes 202 or 212, but which were not bound through the application of a binder agent. In one implementation, the second volume 222 of build material powder may be contained within the same powder bed as was used during the fabrication of sinterable product 200 or sinterable product 210. In other implementations, the second volume 222 of build material powder may be contained within a different powder bed as was used during the fabrication of sinterable product 200 or sinterable product 210. The fabrication of sinterable setter 220 may be carried out using a process substantially similar to or the same as the process used to form sinterable product 206 or sinterable product 210. 85017738

[00035] As further shown by stage 128 and described above with respect to block 30, the sinterable setter 220 is coated with an interface layer 224 of interface material. During such coating or application of the interface material, portions of the interface material being applied may disperse as satellites or misdirected droplets to nontargeted regions. As a result, in those implementations in which setter 220 and its overlying coating or layer 224 are formed in a layer-by-layer fashion, the interface layer material 226 may become distributed and interspersed throughout those portions 223 of volume 222 which are not used to form setter 220 as well as throughout the bound portions of build material powder forming sinterable setter 220.

[00036] As indicated by stage 132 and described above with respect to block 32, a second sinterable setter 230 is fabricated using the build material powder from stage 128 that was not bound with a binding agent and that was possibly contaminated with the interface layer

particles/materials 226. The second sinterable setter 230 may be fabricated using a fabrication process similar to or the same as the fabrication process used to form sinterable setter 220.

[00037] As indicated by arrow 223, the leftover portions of volume 222 form at least a part of the volume 232 of build material powder utilized to form sinterable setter 230. In some implementations, the reused portions of volume 222 may be sufficient to form the entire volume 232, all of the sequentially formed layers of build material powder that are stacked upon one another and which have selected portions bound by a binder agent to form sinterable setter 230 and interface layer 234. In other

implementations, the build material powder being reused from volume 222 may be supplemented with previously leftover build material powder.

[00038] For example, the fabrication of sinterable setter 200 and interface layer 234 may consume 20% of the total volume 222 of build 85017738

material powder. In circumstances where the sinterable setter 230 and its interface layer 234 are the same as the sinterable setter 220 and its interface layer 224, volume 232 may be supplemented so as to replace the 20% of the volume 222 that was consumed such that volume 232 is the same as volume 222. In other implementations, the sinterable setter 230 and its interface layer 234 may be smaller than that of sinterable setter 220 and its interface layer 224 or may have a geometry (size and/or shape) that demands a smaller volume of build material powder for its fabrication. In some implementations, sinterable setter 230 may be entirely formed from what contaminated powder is left over from the fabrication of sinterable setter 220. In still other implementations, the sinterable setter 230 and its interface layer 234 may be larger than the sinterable setter 220 and interface layer 224 or may have a geometry that demands larger volume 232 of build material powder. In such circumstances, the portions of the leftover volume 222 of build material powder may be supplemented with additional build material powder to satisfy the build material powder demands for the fabrication of sinterable setter 230 and interface layer 234.

[00039] As schematically shown by stage 132, the resulting sinterable setter 230 may itself include interface layer material or interface layer material particles interspersed throughout and amongst the body of sinterable supports 230 in addition to the interface layer 234 formed on the exterior surface of the binding agent bound body of the second sinterable setter 230. However, as the main use of setter 230 is to support product 210 during centering, its potential lower degree of structural integrity is tolerable. The reuse or recycling of the leftover contaminated build material powder reduces cost and reduces waste.

[00040] As shown by stage 140, the sinterable product 200 and the coated sinterable support setter 220, 224 are assembled in a supporting relationship in which the coated support setter 220, 224 underlies those portions of the sinterable product 200 which may be susceptible to various 85017738

deformations, bending or sag during sintering. The supporting relationship is such that the interface layer 224 is sandwiched between the sinterable product 226 and the underlying sinterable setter 220.

[00041] As shown by stage 142, the assembly of the sinterable product 200 and the coated sinterable support setter 220, 224 undergoes sintering. In some implementations, the assembly first undergoes a preparatory preheating or“pre-burn” during which most, if not all of the binder material is burnt off or removed from the assembly. The pre-burn temperature is below the sintering temperature of the sinterable build material. Thereafter, the temperature is elevated to a sintering temperature. Such sintering results in a sintered product 250 and a sintered setter 260 within intervening, less sintered interface layer 224. In some implementations, the interface layer 224 may undergo some sintering, but a degree of sintering less than that of product 250 or setter 260. In other implementations, depending upon the temperatures and materials of interface layer 224, interface layer 224 does not undergo any sintering. Because the degree of sintering is less than that of product 250 or setter 260, interface layer 224 has a lower degree of coalescing in forms a weak break line that facilitates the separation of product 250 from setter 260. As shown by stage 144, the sintered product 250 is separated from setter 260 and interface layer 224. Any remnants of interface layer 224 on surfaces of product 250 may be removed through brushing or in other surface treatment methods.

[00042] As shown by stage 150, sinterable product 210 and the coated sinterable setter 230, 234 are assembled in a supporting relationship. This assembly is similar to the assembly described above with respect to stage 140. Unlike the assembly resulting from stage 140, the assembly in stage 150 utilizes sinterable setter 230 which is formed from build material powder contaminated with interface layer materials 226. 85017738

[00043] As shown by stage 152, the assembly undergoes sintering.

Such sintering may be similar to the sintering process described above with respect to stage 142. For example, the assembly may be first exposed to a lower pre-burn temperature followed by a higher sintering temperature, such as in a sintering oven. During such sintering, the coated sinterable setter 230, 234 supports those portions of sinterable product 210 that may be susceptible to drooping or sagging during sintering. Such sintering produces a sintered product 270, a sintered support setter 280, and a less sintered interface layer 234. In some implementations, the interface layer 234 may undergo some sintering, but a degree of sintering less than that of product 270 or setter 280. In other implementations, depending upon the temperatures and materials of interface layer 234, interface layer 234 does not undergo any sintering. Because the degree of sintering is less than that of product 270 or setter 280, interface layer 234 has a lower degree of coalescing in forms a weak break line that facilitates defined and controlled separation of product 270 from setter 280. As shown by stage 154, the sintered product 270 is separated from setter 280 and interface layer 234. Any remnants of interface layer 234 on surfaces of product 270 may be removed through brushing or in other manners.

[00044] Figures 3A and 3B together schematically illustrate an example 3D fabrication system 300. System 300 may carry out method 20. System 300 facilitates the fabrication and use of“live setters” and the provision of an interface layer on surfaces of the sinterable setter. Rather than disposing of the leftover powder that has become contaminated, system 300 reuses or recycles the potentially contaminated powder. System 300 facilitates the fabrication of 3D powder sinterable setters using leftover or recycled powder that may have been contaminated with interface layer materials during the prior fabrication of an interface layer coated 3D sinterable setter. At the same time, system 300 isolates the potentially contaminated powder that is being reused for the fabrication of setters from the uncontaminated powder used to fabricate the sinterable product itself 85017738

so as to maintain the quality of the sinterable product and the final 3D product. System 300 comprises powder bed 320 , powder supply bin 322, powder supply bin 324, binder applicator 328, interface applicator 330, input 334, powder passage 336, powder passage 337, powder passage 339, powder transfer system 340 and controller 342 .

[00045] Powder bed 320 comprises a container having an interior for supporting and containing a mass of particulate build material powder 346. Powder supply bin 322 comprises a bin or container containing virgin or otherwise uncontaminated powder to be supplied to the interior of bed 320 when fabricating sinterable setters and to replenish or supplement powder bed 320 with additional 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.

[00046] Powder supply bin 324 comprises a bin or container containing previously used, leftover powder that may have become contaminated with interface layer materials, such as ceramics. Powder supply bin 324 supplies such contaminated sinterable build material to powder bed 320 during the fabrication of sinterable setters in diagram 3B.

[00047] Binder applicator 328 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 346, wherein the binder material binds the powder together. In one implementation, binder applicator 328 applies a binder material selected from a group of binder material such as a latex based ink, uv curable material, or thermally curable material.

[00048] Interface applicator 330 comprise a source or reservoir of interface layer material and an associated applicator that selectively applies 85017738

the interface material or interface layer material either onto the powder 346 or onto already bound powder 346. The interface layer material comprises a powder or particulates of a material having a higher sintering temperature than that of the powder or build material 346. 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 Si3N4or combinations thereof.

[00049] In one implementation, binder applicator 328 and interface applicator 330 are provided as print bars that include a multitude or an array of ejection nozzles that are selectively controlled and moved above the powder in bed 320 to selectively apply the binder and the interface layer material, respectively, at precisely defined locations.

[00050] Figure 4 is a block diagram schematically illustrating an example nozzle or fluid ejector 450 that may be used as part of binder applicator 328 or interface applicator 330. Fluid ejector 450 may be carried by print bar

451 that is controllably movable in a single dimension, two dimensions or three dimensions above the powder 342 in bed 424. Each of such fluid ejectors 450 comprises a nozzle chamber 452, a nozzle orifice 454 and a fluid actuator 456.

[00051] Chamber 452 comprises a volume containing a volume of liquid forming the binder as in the case of binder applicant 328 or carrying the liquid with the interface layer material as in the case of interface applicator 330. Nozzle orifice 454 comprises an opening extending from chamber

452 through which the liquid is ejected.

[00052] Fluid actuator 456 comprises a mechanism that displaces fluid/liquid within chamber 452 to expel a stream or droplets of fluid through orifice 454 towards precise locations. In some examples, fluid actuator 456 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. 85017738

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 452 to expel fluid through orifice 454. The fluid or liquid carrying the interface materials or particles and jetted onto the powder build material is subsequently burnt off or evaporated during sintering or prior to sintering.

[00053] In other examples, the fluid actuator 452 may comprise a piezo membrane based actuator, and electrostatic membrane actuator, a mechanical/impact driven membrane actuator, a magneto restrictive 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.

[00054] Input 334 comprises an interface by which a user or person may enter commands and input information to system 300. Input 334 may comprise a touchpad, a touch screen, a keyboard, a mouse, a stylus, a microphone which speech recognition software capabilities and the like. Input 334 may be utilized to input geometries of the final product which is to be formed using the sinterable support setter and coating to be fabricated by system 300. Input 334 may be utilized to input geometries of a sinterable product which is to be supported by the coated sinterable support setter that is to be formed by system 300. Input 334 may be used to input characteristics of the powder build material, characteristics of the 85017738

binder and/or characteristics of the interface layer material. Input 334 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.

[00055] Powder passage 336 comprises a conduit extending from powder bed 342 to powder bin 324. Powder passage 336 delivers build material powder that has been potentially contaminated with interface layer materials from powder bed 320 to powder bin 324. Powder passage 339 comprises a conduit extending from powder bin 324 to powder bed 320. Powder passage 339 supplies the potentially contaminated build material powder that is being recycled back to powder bed 320. Powder passage 337 comprises a passage extending from powder bin 322 to powder bed 320. Powder is delivered through powder passage 337 to powder bed 320.

[00056] Powder transfer system 340 comprises system that moves leftover powder in the powder bed 320 to the powder bin 324 following the forming of or fabrication of a sinterable support setter coated with an interface layer in powder bed 320. Powder transfer system 340 additionally delivers the contaminated or leftover powder containing interface layer materials from powder bin 324 to powder bed 320 and delivers virgin or uncontaminated powder from powder bin 322 to powder bed 320 such as in those instances where the leftover powder supplied from bin 322 is insufficient for forming a subsequent sinterable setter. In one

implementation, powder transfer system 340 may comprise a switch that may be selectively actuated to power an auger, conveyor, blower or vacuum within passage 336. In one implementation, powder transfer system 340 may include a selectively actuatable valve for directing a vacuum or a blower to move powder along passages 336, 337 and 339.

[00057] Controller 342 comprises a processor 346 and associated non- transitory computer-readable medium or memory 348 for controlling system 85017738

300. Memory 346 comprises a non-transitory computer-readable medium containing instructions for directing the processor 348 to prompt for input of data or commands, to analyze such input data and commands, to receive sensed feedback from sensors of system 300 and analyze such feedback, and to output control signals controlling the supply of powder from powder bins 322, 324, the operation of binder applicator 328 and interface applicator 330, and the transfer of powder by powder transfer system 340. Controller 342 may precisely control the fabrication of a sinterable support setter based upon characteristics of the sinterable product, the interface layer and the materials thereof.

[00058] Figures 3A and 3B illustrate system 300 in two different operating states. Figure 3A illustrates system 300 carrying out blocks 24 and 26 as described above to form a first sinterable setter. In particular, Figure 3A illustrates controller 342 outputting control signals causing powder bin 322 (with a valve, auger or other flow control mechanism) to supply powder bed 320 with powder from powder bin 322 for the fabrication of the interface layer 224, 324 coated sinterable setter 220, 230 described above.

[00059] Following the fabrication of the coated sinterable setter 220, 230 in figure 3A, controller 342 may output control signals to powder transfer system 340 withdrawing the potentially contaminated sinterable build material powder from bed 320 and moving such potentially contaminated sinterable build material powder to powder bin 324 through passage 336 for use in the subsequent fabrication of additional sinterable setters. Powder transfer system 340 controls the return of leftover build material powder from bed 320 to powder bin 324.

[00060] Figure 3B illustrates system 300 carrying out blocks 28 and 30 as described above to form a second sinterable setter 220, 230 coated with an interface layer 224, 324. In particular, Figure 3B illustrates controller 85017738

342 outputting control signals causing powder bin 324 (with a valve, auger or other flow control mechanism) to supply powder bed 320 with powder from powder bin 324 for the fabrication of the sinterable setter such as sinterable product 220 or 230 with interface layers 224 or 234 as described above. In some implementations, depending upon the volume of powder used to form sinterable setter 220, 230, controller 342 may output control signals causing powder transfer system 340 to supplement or add to the supply of powder within bed 320 using uncontaminated powder from powder bin 322.

[00061] 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

85017738 WHAT IS CLAIMED IS:

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

fabricating a first sinterable product in a first volume of powder;

fabricating a second sinterable product from unused portions of the powder of the first volume;

fabricating a first sinterable setter to support the first sinterable product in a second volume of powder;

coating the first sinterable setter with an interface layer while the sinterable setter is within the second volume of powder;

fabricating a second sinterable setter from unused portions of the powder of the second volume; and

form a second interface layer on the second sinterable setter while the second sinterable setter is within the second volume of powder.

2. The 3D fabrication method of claim 1 further comprising fabricating a third sinterable setter in a third volume of powder at least partially comprising leftover portions of the powder of the second volume.

3. The 3D fabrication method of claim 1 further comprising fabricating the sinterable product in a first powder bed, wherein the second volume of powder is within a second powder bed, different than the first powder bed, during fabrication of the first sinterable setter.

4. The 3D fabrication method of claim 1 further comprising adding powder to the portions of the second volume that remain leftover following 85017738

fabrication of the first sinterable setter before fabrication of the second sinterable setter.

5. The 3D fabrication method of claim 1 further comprising: assembling the sinterable product with the first interface coating and the first sinterable setter in a supporting relationship in which the first sinterable setter with the first interface coating supports the sinterable product; sintering the sinterable product and the sinterable setter with the interface layer while in the supporting relationship to form a sintered product and a sintered setter; and separating the sintered product from the sintered setter with assistance from the interface layer.

6. The 3D fabrication method of claim 1 , wherein fabricating the first sinterable setter comprises sequentially binding selected portions of different layers of the powder with a binding agent and wherein coating the sinterable setter with the interface layer comprises sequentially applying an interface layer material to selected portions of the different layers of the powder adjacent those portions of the layers bound with the binding agent.

7. The 3D fabrication method of claim 6, wherein the interface layer material is applied by jetting a liquid containing the interface layer material. 85017738

8. The 3D fabrication method of claim 1 , wherein the first sinterable setter and the second sinterable setter each have interface layer material interspersed throughout.

9. A three-dimensional (3D) fabrication system comprising: a powder bed; a binder applicator to selectively apply binder to powder within the powder bed to form a first sinterable setter; an interface layer applicator to selectively apply an interface material to the first sinterable setter within the powder bed; a first powder bin; a second powder bin; a first powder passage from the powder bed to the first powder bin; a second powder passage from the powder bed to the second powder bin; a powder transfer system: (1 ) to move leftover powder in the powder bed to the first powder bin following the forming of the sinterable setter in the powder bed and (2) to supply leftover powder from the second powder bin to the powder bed prior to forming of a second sinterable setter in the powder bed; and 85017738

a controller to output control signals causing the powder transfer system to move the leftover powder in the powder bed to the first powder bin following the forming of the first sinterable setter in the powder bed and to output control signals causing the powder transfer system to move leftover powder from the first powder bin and the second powder bin to the powder bed to form a volume of powder for forming the second sinterable setter. .

10. The 3D fabrication system of claim 6, wherein the interface layer applicator comprises a bar movable over the powder bed and supporting binder jetting nozzles, each of the binder jetting nozzles comprising: an ejection orifice; and a fluid actuator.

11. The 3D fabrication system of claim 7, wherein the fluid actuator comprises a thermal resistive fluid actuator.

12. The 3D fabrication system of claim 6, wherein the interface layer applicator is to selectively apply a ceramic material to the bound powder within the powder bed to form the sinterable setter.

13. The 3D fabrication system of claim 6 further comprising a second powder transfer system to selectively supply the powder bed with powder from either the first powder bin or the second powder bin.

14. A three-dimensional (3D) powder sinterable setter comprising: a main body comprising: 85017738

a powder comprising sinterable particulates interspersed throughout the main body;

interface material particulates interspersed throughout the main body and amongst the sinterable particulates; and a binder binding the sinterable particulates and the interface material particulates to form the main body; and, a layer of the interface material extending over the main body.

15. The sinterable setter of claim 1 1 , wherein the sinterable particulates comprise metallic particulates and wherein interface material comprises a ceramic material.