# US 11,077,632 B2 · Microwave post-processing for additive manufacturing > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,077,632 B2 - Document ID: US11077632B2 - Status: Granted - Kind: B2 - Application number: 14/212,399 - Filed: 2014-03-14 - Published: 2016-12-15 - Granted: 2021-08-03 - Earliest claimed: 2013-03-15 - Assignees: 3D Systems, Inc. - Applicants: 3D Systems, Inc. - Inventors: Luis N Folgar; Carlos E Folgar; Francisco Folgar; Christian E Folgar; Jim Williams - Web page: https://patentgrep.com/patent/US11077632B2 ## CPC - B29C 71/04: by wave energy or particle radiation {, e.g. for curing or vulcanising preformed articles (during moulding, e.g. in a mould B29C35/08)} - B29C 64/30: Auxiliary operations or equipment - H05B 6/64: Heating using microwaves {(containers, packaging elements or packages specially adapted to be heated by microwaves B65D81/3446)} - B29C 64/364: Conditioning of environment - B29C 2035/0855: {using microwave} - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL ## Abstract In one aspect, methods of post-processing an object made by additive manufacturing are described herein. In some embodiments, a method of post-processing an object described herein comprises providing the object in a microwave absorptive state and exposing the object in the absorptive state to a field of microwave radiation. In some cases, providing an object in a microwave absorptive state comprises heating the object, including by non-microwave heating. Moreover, in some embodiments, the object is exposed to a uniform or substantially uniform field of microwave radiation in a microwave cavity. In addition, in some instances, exposing an object to a field of microwave radiation in a manner described herein comprises increasing the density of the object and/or reducing the volume of the object, including in an isotropic or substantially isotropic manner. ## Claims ### Claim 1 A method of post-processing a three-dimensional object made by additive manufacturing, the method comprising: heating the three-dimensional object to provide the three-dimensional object in a microwave absorptive state after forming the three-dimensional object by an additive manufacturing method; and exposing the three-dimensional object in the absorptive state to a field of microwave radiation after providing the three-dimensional object made by additive manufacturing in the absorptive state, wherein the heating comprises heating the three-dimensional object by non-microwave heating, and wherein the three-dimensional object in the absorptive state has a dielectric loss between 0.1 and 5 at one or more frequencies of the field of microwave radiation. ### Claim 2 (depends on 1) The method of claim 1, wherein exposing the object to the field of microwave radiation is carried out in a microwave cavity. ### Claim 3 (depends on 1) The method of claim 1, wherein the field is a uniform or substantially uniform field of microwave radiation. ### Claim 4 (depends on 1) The method of claim 1, wherein exposing the object to the field of microwave radiation comprises increasing the true density or bulk density of the object. ### Claim 5 (depends on 1) The method of claim 1, wherein exposing the object to the field of microwave radiation comprises reducing the volume of the object. ### Claim 6 (depends on 5) The method of claim 5, wherein the volume of the object is reduced isotropically or substantially isotropically. ### Claim 7 (depends on 1) The method of claim 1 further comprising drying the object prior to exposing the object to the field of microwave radiation. ### Claim 8 (depends on 1) The method of claim 1 further comprising supporting the object with a support structure during exposure of the object to the field of microwave radiation, wherein the support structure facilitates changes in the size of the object. ### Claim 9 (depends on 8) The method of claim 8, wherein the support structure is a form fitting structure disposed on the exterior surface of the object. ### Claim 10 (depends on 8) The method of claim 8, wherein supporting the object with a support structure comprises disposing the object within a box, bag, or mold. ### Claim 11 (depends on 8) The method of claim 8, wherein supporting the object with a support structure comprises coating the exterior surface of the object with a support material. ### Claim 12 (depends on 1) The method of claim 1 further comprising placing the object within a thermally insulating container prior to exposing the object to the field of microwave radiation. ### Claim 13 (depends on 1) The method of claim 1 further comprising applying a pressure to the object during exposure to the field of microwave radiation. ### Claim 14 (depends on 1) The method of claim 1, wherein providing the object in a microwave absorptive state comprises heating the object to a temperature between 100° C. and 250° C. by non-microwave heating. ### Claim 15 (depends on 1) The method of claim 1, wherein: providing the object in a microwave absorptive state comprises heating the object to a temperature between 100° C. and 250° C. by non-microwave heating; and exposing the object to the field of microwave radiation comprises increasing the true density or bulk density of the object and reducing the volume of the object isotropically or substantially isotropically. ### Claim 16 (depends on 1) The method of claim 1, wherein exposing the object to the field of microwave radiation alters internal physical structure of the object. ### Claim 17 (depends on 4) The method of claim 4, wherein the true density or bulk density is increased via alteration of physical structure of the object. ### Claim 18 (depends on 5) The method of claim 5, wherein the volume is reduced via alteration of physical structure of the object. ### Claim 19 (depends on 1) The method of claim 1, wherein exposing the three-dimensional object in the absorptive state to a field of microwave radiation does not substantially affect the feature resolution of the three-dimensional object.