# US 11,440,099 B2 · Processes and systems for double-pulse laser micro sintering > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,440,099 B2 - Document ID: US11440099B2 - Status: Granted - Kind: B2 - Application number: 16/427,638 - Filed: 2019-05-31 - Published: 2020-01-09 - Granted: 2022-09-13 - Earliest claimed: 2018-07-03 - Assignees: Purdue Research Foundation - Applicants: Purdue Research Foundation - Inventors: Benxin Wu - Web page: https://patentgrep.com/patent/US11440099B2 ## CPC - B23K 26/082: Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head - B22F 10/28: Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM] - B22F 10/36: of energy beam parameters - B22F 10/50: Treatment of workpieces or articles during build-up, e.g. treatments applied to fused layers during build-up - B22F 12/43: pulsed; frequency modulated - B22F 12/45: Two or more - B23K 26/0608: {in the same heat affected zone [HAZ] (B23K26/0613, B23K26/0619 take precedence)} - B23K 26/0622: by shaping pulses - B23K 26/0624: {using ultrashort pulses, i.e. pulses of 1 ns or less} - B23K 26/34: Laser welding for purposes other than joining - B23K 26/356: by shock processing - B33Y 10/00: Processes of additive manufacturing - B33Y 30/00: Apparatus for additive manufacturing; Details thereof or accessories therefor - B22F 10/38: to achieve specific product aspects, e.g. surface smoothness, density, porosity or hollow structures - B22F 12/44: characterised by the configuration of the radiation means - B22F 2999/00: Aspects linked to processes or compositions used in powder metallurgy - B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM - 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 - 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 ## Abstract Processes and systems that include one or more laser beam sources configured to provide laser irradiation with one or more laser pulse groups to at least a portion of powder particles on a solid surface at one or multiple locations thereof. Sintering laser pulse(s) is provided to induce coalition of at least some of the powder particles into a more continuous medium, and pressing laser pulse(s) is provided to produce pressure pulse(s) on at least a portion of the powder particles and/or the more continuous medium. Laser pulse groups may include one or more of the sintering laser pulses followed by one or more of the pressing laser pulses with a time delay between a last of the sintering laser pulse(s) and a first of the pressing laser pulse(s). ## Claims ### Claim 1 A laser sintering process comprising: providing powder particles on a solid surface so that at least a portion of the powder particles forms a material surface; and then or simultaneously laser irradiating a target surface of the material surface with one or more laser pulse groups at one or multiple locations to induce coalition of at least some of the powder particles at the target surface into a more continuous medium comprising a mass formed by at least two interconnected powder particles; wherein at least one of the one or more laser pulse group(s) comprises: one or more sintering laser pulses that irradiate at least first irradiated target surface locations of the target surface followed by one or more pressing laser pulses that irradiate at least second irradiated target surface locations of the target surface, wherein the one or more pressing laser pulses have a peak power density at the second irradiated target surface locations that is higher than a peak power density of the one or more sintering laser pulses at the first irradiated target surface locations; a time delay at the target surface between a last sintering laser pulse of the one or more sintering laser pulses and a first pressing laser pulse of the one or more pressing laser pulses; and inducing, with the first pressing laser pulse, a pressure pulse onto the target surface by vaporizing material at the target surface and/or creating a plasma plume at the target surface, wherein at the moment right before the first pressing laser pulse arrives at the target surface, at least some material in at least part of the target surface melted or partially melted at least partially due to irradiation of the one or more sintering laser pulses still remains melted or at least partially melted when irradiated by the first pressing laser pulse. ### Claim 2 (depends on 1) The laser sintering process of claim 1, wherein the one or more sintering laser pulses of the at least one laser pulse group comprises two or more sintering laser pulses and a temporal distance between the last sintering laser pulse and the first pressing laser pulse is different from at least one of the temporal distances between two adjacent sintering laser pulses of the two or more sintering laser pulses in the at least one laser pulse group. ### Claim 3 (depends on 1) The laser sintering process of claim 1, wherein at least one sintering laser pulse of the one or more sintering laser pulses is different from at least one pressing laser pulse of the one or more pressing laser pulses in at least one parameter or characteristic selected from the group consisting of laser pulse duration, and laser pulse energy and any combination thereof. ### Claim 4 (depends on 1) The laser sintering process of claim 1, wherein the first pressing laser pulse is sent out while the material surface that is going to receive radiation from the first pressing laser pulse is at least partially at temperature(s) higher than about 25° C. from the last sintering laser pulse. ### Claim 5 (depends on 1) The laser sintering process of claim 1, wherein the first pressing laser pulse is sent out while the material in the at least part of the target surface is still melted from the last sintering laser pulse. ### Claim 6 (depends on 1) The laser sintering process of claim 1, wherein the more continuous medium has at least one feature that is smaller than one millimeter in at least one direction. ### Claim 7 (depends on 1) The laser sintering process of claim 1, wherein each pulse duration of each and every one of the one or more sintering laser pulses is in the range of 1 nanosecond (ns) to 1000 ns. ### Claim 8 (depends on 1) The laser sintering process of claim 1, wherein the powder particles are metallic particles. ### Claim 9 (depends on 1) The laser sintering process of claim 1, wherein the laser irradiating step occurs after at least a portion of the powder particles is provided on the solid surface. ### Claim 10 (depends on 1) The laser sintering process of claim 1, further comprising at least a second laser pulse group that comprises: one or more sintering laser pulses followed by one or more pressing laser pulses, wherein at least one of the one or more sintering laser pulses is different from at least one of the one or more pressing laser pulses in at least one parameter or characteristic selected from the group consisting of laser pulse duration, laser pulse energy, peak laser power density within the laser pulse at the target surface, laser spot size on the target surface, laser beam wavelength, relation of laser power versus time within the laser pulse, spatial profile of laser beam intensity on the target surface, and any combination thereof; and a time delay between a last one of the one or more sintering laser pulses and a first one of the one or more pressing laser pulses.