# US 11,998,987 B2 · 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 11,998,987 B2 - Document ID: US11998987B2 - Status: Granted - Kind: B2 - Application number: 15/831,779 - Filed: 2017-12-05 - Published: 2019-06-06 - Granted: 2024-06-04 - 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/US11998987B2 ## 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 sintered article comprising: a sintered interior having a shape and comprising a sintered loose powder component; and a sintered exterior having a sintered powder composition that comprises an organic binder, the sintered exterior forming 5-20 volume percent of the sintered article and being continuous with the sintered interior, wherein a density gradient or porosity gradient exists between the sintered interior and sintered exterior, wherein the sintered interior and the sintered exterior are made of different materials. ### Claim 2 (depends on 1) The sintered article of claim 1, wherein the sintered exterior has thickness of 0.1-1 mm. ### Claim 3 (depends on 1) The sintered article of claim 1, wherein average density of the sintered article is at least 98 percent theoretical density. ### Claim 4 (depends on 1) The sintered article of claim 1, wherein the sintered interior is greater than 99 percent theoretical density, and the sintered exterior is 92-95 percent theoretical density. ### Claim 5 (depends on 1) The sintered article of claim 1, wherein the sintered exterior has thickness less than 1 mm. ### Claim 6 (depends on 1) The sintered article of claim 1, wherein the sintered powder composition and the sintered loose powder component comprise a powder independently selected from the group consisting of powder metal and powder alloy. ### Claim 7 (depends on 1) The sintered article of claim 1, wherein the sintered powder composition and the sintered loose powder component comprise sintered cemented carbide particles. ### Claim 8 (depends on 1) The sintered article of claim 1, wherein the sintered powder composition and the sintered loose powder component comprise particles that are substantially monodisperse. ### Claim 9 (depends on 1) The sintered article of claim 1, wherein the sintered powder composition and the sintered loose powder component comprise particles that have average particle size of 5 to 90 μm. ### Claim 10 (depends on 1) The sintered article of claim 1, wherein the sintered powder composition and the sintered loose powder component comprise particles that have average particle size of 10 to 50 μm. ### Claim 11 (depends on 1) The sintered article of claim 1, wherein the sintered powder composition and the sintered loose powder component comprise a mixture of spherical particles and irregularly shaped particles. ### Claim 12 (depends on 1) The sintered article of claim 1, wherein the sintered powder composition and the sintered loose powder component comprise the same powder. ### Claim 13 (depends on 1) The sintered article of claim 1, wherein the powder of the sintered powder composition and the sintered loose powder component have the same average particle size. ### Claim 14 A sintered article comprising: a sintered interior having a shape and comprising a sintered loose powder component; and a sintered exterior having a sintered powder composition that comprises an organic binder, the sintered exterior forming 10-30 volume percent of the sintered article and being continuous with the sintered interior, wherein a density gradient or porosity gradient exists between the sintered interior and sintered exterior, and an average particle size of a powder of the sintered loose powder component and of the sintered powder composition is the same, wherein the sintered interior and the sintered exterior are made of different materials. ### Claim 15 (depends on 14) The sintered article of claim 14, wherein the average particle size is 10-50 μm. ### Claim 16 (depends on 14) The sintered article of claim 14, wherein the sintered powder composition and the sintered loose powder component comprise sintered cemented carbide particles. ### Claim 17 A sintered article comprising: a sintered interior comprising a sintered loose powder component; and a sintered exterior having a sintered powder composition that comprises an organic binder, 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, and average density of the sintered article increases linearly with decreasing volume percent of the sintered exterior, wherein the sintered interior and the sintered exterior are made of different materials. ### Claim 18 (depends on 1) The sintered article of claim 1, wherein the sintered loose powder component is continuously present in the sintered interior across a cross-section of the sintered article. ### Claim 19 (depends on 14) The sintered article of claim 14, wherein the sintered loose powder component is continuously present in the sintered interior across a cross-section of the sintered article. ### Claim 20 (depends on 17) The sintered article of claim 17, wherein the sintered loose powder component is continuously present in the sintered interior across a cross-section of the sintered article.