# US 2019/0168299 A1 · Additive manufacturing techniques and applications thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0168299 A1 - Document ID: US20190168299A1 - Status: Published application - Kind: A1 - Application number: 15/831,779 - Filed: 2017-12-05 - Published: 2019-06-06 - Earliest claimed: 2017-12-05 - Assignees: Kennametal Inc. - Applicants: Kennametal Inc. - Inventors: Paul D. Prichard; Kevin Gamble; John Skwara - Web page: https://patentgrep.com/patent/US20190168299A1 ## CPC - B22F 7/06: of composite workpieces or articles from parts, e.g. to form tipped tools {(B22F7/002 takes precedence)} - B22F 10/14: by jetting of binder onto a bed of metal powder - B22F 10/38: to achieve specific product aspects, e.g. surface smoothness, density, porosity or hollow structures - B28B 1/001: {Rapid manufacturing of 3D objects by additive depositing, agglomerating or laminating of material (selective deposition modelling of metallic powder B22F10/00; rapid manufacturing of 3D objects in general and in particular of plastics B29C64/00)} - B33Y 10/00: Processes of additive manufacturing - B33Y 70/00: Materials specially adapted for additive manufacturing - B33Y 80/00: Products made by additive manufacturing - B22F 10/28: Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM] - B22F 2207/17: density or porosity gradients - B22F 2301/15: Nickel or cobalt - B22F 2301/35: Iron - B22F 2998/10: Processes characterised by the sequence of their steps - C22C 29/08: based on tungsten carbide - C22C 33/02: by powder metallurgy - Y02P 10/25: Process efficiency - Y10T 428/12021: having composition or density gradient or differential porosity - B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER - B28B: SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER (foundry moulding B22C; working stone or stone-like material B28D; shaping of substances in a plastic state, in general B29C; making layered products not composed wholly of these substances B32B) - B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING - C22C: ALLOYS (treatment of alloys C21D, C22F) - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract In one aspect, a method of making a sintered article comprises providing a composite article comprising a porous exterior printed from a powder composition via one or more additive manufacturing techniques, the porous exterior defining an interior volume and providing a loose powder component in the interior volume. The porous exterior and loose powder component are simultaneously sintered to provide the sintered article comprising a sintered interior and sintered exterior. ## Claims ### Claim 1 A method of making a sintered article comprising: providing a composite article including a porous exterior printed from a powder composition via one or more additive manufacturing techniques, the porous exterior defining an interior volume; providing a loose powder component in the interior volume; and simultaneously sintering the porous exterior and loose powder component to provide the sintered article comprising a sintered interior and sintered exterior. ### Claim 2 (depends on 1) The method of claim 1, wherein the porous exterior forms less than 60 volume percent of the composite article. ### Claim 3 (depends on 1) The method of claim 1, wherein the porous exterior forms 5-30 volume percent of the composite article. ### Claim 4 (depends on 1) The method of claim 1, wherein average density of the sintered article is at least 97 percent theoretical density. ### Claim 5 (depends on 1) The method of claim 1, wherein average density of the sintered article is at least 98 percent theoretical density. ### Claim 6 (depends on 1) The method of claim 1 comprising a density gradient between the sintered interior and sintered exterior. ### Claim 7 (depends on 6) The method of claim 6, wherein the sintered interior is greater than 99 percent theoretical density. ### Claim 8 (depends on 7) The method of claim 7, wherein the sintered exterior is 92-95 percent theoretical density. ### Claim 9 (depends on 1) The method of claim 1, wherein the sintered interior has less than 2 volume percent porosity. ### Claim 10 (depends on 1) The method of claim 1, wherein the composite article is at least 50 percent tap density of the loose powder component. ### Claim 11 (depends on 1) The method of claim 1, wherein the composite article is at least 55 percent tap density of the loose powder component. ### Claim 12 (depends on 1) The method of claim 1, wherein the powder composition of the porous exterior and the loose powder component have the same composition. ### Claim 13 (depends on 1) The method of claim 1, wherein the powder composition of the porous exterior and the loose powder component are of differing compositions. ### Claim 14 (depends on 1) The method of claim 1, wherein the powder composition of the porous exterior and the loose powder component are independently selected from the group consisting of powder metal and powder alloy. ### Claim 15 (depends on 14) The method of claim 14, wherein the powder alloy comprises cobalt-based alloy, nickel-based alloy, iron based alloy or combinations thereof. ### Claim 16 (depends on 1) The method of claim 1, wherein the powder composition of the porous exterior and the loose powder component comprise sintered cemented carbide particles. ### Claim 17 (depends on 16) The method of claim 16, wherein the sintered cemented carbide particles have apparent density of at least 6 g/cm3. ### Claim 18 (depends on 1) The method of claim 1, wherein the porous exterior has thickness less than or equal to 0.5 mm. ### Claim 19 (depends on 1) The method of claim 1, wherein the porous exterior is formed around the loose powder component. ### Claim 20 (depends on 1) The method of claim 1, wherein the loose powder component is added to the interior volume. ### Claim 21 (depends on 1) The method of claim 1, wherein the sintered interior and sintered exterior are continuous with one another. ### Claim 22 (depends on 1) The method of claim 1 further comprising vibrating the loose powder component. ### Claim 23 (depends on 1) The method of claim 1 further comprising printing one or more lattice structures in the interior volume. ### Claim 24 (depends on 23) The method of claim 23, wherein the lattice structures span the interior volume, contacting sections of the porous exterior. ### Claim 25 (depends on 23) The method of claim 23, wherein the loose powder component surrounds the lattice structures. ### Claim 26 (depends on 1) The method of claim 1, wherein the additive manufacturing technique is binder jetting. ### Claim 27 (depends on 1) The method of claim 1, wherein the porous exterior is partially sintered and exhibits greater than 50 percent porosity. ### Claim 28 (depends on 1) The method of claim 1 further comprising removing at least a portion of the sintered exterior. ### Claim 29 A sintered article comprising: a sintered interior and sintered exterior, the sintered exterior forming less than 30 volume percent of the sintered article, wherein a density gradient or porosity gradient exists between the sintered interior and sintered exterior. ### Claim 30 (depends on 29) The article of claim 29, wherein the sintered exterior forms 5-20 volume percent of the sintered article. ### Claim 31 (depends on 29) The article of claim 29, wherein the sintered exterior has thickness of 0.1-1 mm. ### Claim 32 (depends on 29) The article of claim 29, wherein average density of the sintered article is at least 98 percent theoretical density. ### Claim 33 (depends on 29) The article of claim 29, wherein the sintered interior is greater than 99 percent theoretical density, and the sintered exterior is 92-95 percent theoretical density. ### Claim 34 (depends on 29) The article of claim 29, wherein the sintered exterior has thickness less than 0.5-1 mm. ### Claim 35 (depends on 29) The article of claim 29, wherein powder compositions of the sintered interior and sintered exterior are independently selected from the group consisting of powder metal and powder alloy. ### Claim 36 (depends on 28) The article of claim 28, wherein powder compositions of the sintered interior and sintered exterior comprise sintered cemented carbide particles.