Supports for sintering additively manufactured parts

Patent metadata

Field	Value
Publication number	US-2018162060-A1
Application number	US-201815892726-A
Country	US
Kind code	A1
Filing date	Feb 9, 2018
Priority date	Dec 2, 2016
Publication date	Jun 14, 2018
Grant date	—

Abstract

According to one aspect, embodiments herein provide a method comprising forming a shrinking platform of model material above a build plate, the model material including sinterable metal particles and a first binder, forming a support structure of the model material extending up from the shrinking platform, forming a first portion of the part from successive layers of the model material above the support structure, forming a release layer intervening between a surface of the part and an opposing surface of the support structure or between a surface of the shrinking platform and an opposing surface of the build plate, the release layer including a dispersed ceramic powder and a second binder, and supporting the part, the release layer, and the support structure upon the shrinking platform to form a platform-integrating part assembly, the support structure being configured to prevent the first portion from distorting from gravitational force during sintering.

First claim

What is claimed is:

1 . A method of reducing distortion in an additively manufactured part, comprising:
forming a shrinking platform of model material above a build plate, the model material including sinterable metal particles and a first binder; forming a support structure of the model material extending up from the shrinking platform; forming a first portion of the part from successive layers of the model material above the support structure; forming a release layer intervening between a surface of the part and an opposing surface of the support structure or between a surface of the shrinking platform and an opposing surface of the build plate, the release layer including a dispersed ceramic powder and a second binder; and supporting all of the part, the release layer, and the support structure upon the shrinking platform to form a platform-integrating part assembly, wherein the platform-integrating part assembly is configured to be debound and sintered as a whole, and the support structure is configured to prevent the first portion of the part from distorting from gravitational force during sintering of the platform-integrating part assembly.

2 . The method according to claim 1 , wherein forming the release layer comprises forming the release layer intervening between a non-horizontal surface of the part and the opposing surface of the support structure, the non-horizontal surface of the part including at least one of a vertical surface, a curved surface, and a surface angled with respect to horizontal.

3 . The method according to claim 1 , wherein forming the release layer comprises forming the release layer to intervene between the surface of the part and the opposing surface of the shrinking platform, and wherein the method further comprises:
forming a first portion of the part from successive layers of the model material upon the release layer and directly opposing the shrinking platform.

4 . The method according to claim 1 , further comprising:
debinding the first binder and second binder within the platform-integrating part assembly simultaneously and in a same chamber; and heating the platform-integrating part assembly to a temperature sufficient to simultaneously sinter and densify all of the shrinking platform, the support structure, and the part together at a uniform rate as neighboring metal particles undergo mass diffusion, and to powderize the release layer to leave loose ceramic powder between the opposing surfaces.

5 . The method according to claim 4 , wherein forming the release layer comprises forming the release layer to intervene between the surface of the shrinking platform and the opposing surface of the build plate, and wherein the loose ceramic powder adjacent the model material surface of the shrinking platform promotes sliding between the shrinking platform and the build plate during sintering to reduce distortion.

6 . The method according to claim 4 , wherein forming the release layer comprises forming the release layer to intervene between the surface of the part and the opposing surface of the support structure, and wherein the loose ceramic powder adjacent the model material surface of the part separates the part from the support structure and allows the part to be readily removed from the support structure after sintering.

7 . The method according to claim 4 , wherein forming the shrinking platform comprises forming the shrinking platform to form a foundation for the support structure, all portions of the part commonly densifying from lateral positions located to be supported by the foundation of the shrinking platform, and wherein the shrinking platform holds the part and the support structure in relative position during densification of the same model material and prevents movement of the support structure versus the part during densification that tends to distort the part.

8 . A method of reducing distortion in an additively manufactured part, comprising:
forming a shrinking platform of model material, the model material including sinterable metal particles and a first binder; forming a first support structure of the model material in a location above the shrinking platform; forming a first composite release layer above and upon the first support structure, the first composite release layer including a dispersed ceramic powder and a second binder; and forming the part from successive layers of the model material above and upon the first composite release layer and opposing the first support structure, wherein the part, first composite release layer, and first support structure are all supported upon the shrinking platform as a platform-integrating part assembly, wherein the platform-integrating part assembly is configured to be debound and sintered as a whole, and wherein the first support structure is configured to prevent the part from distorting from gravitational force during sintering.

9 . The method according to claim 8 , wherein forming the first composite release layer comprises forming the first composite release layer to intervene at a non-horizontal surface of the part opposing a surface of the first support structure, the non-horizontal surface of the part including at least one of a vertical surface, a curved surface, and a surface angled with respect to horizontal.

10 . The method according to claim 8 , further comprising:
debinding the first binder and second binder within the platform-integrating part assembly simultaneously and in a same chamber; and heating the platform-integrating part assembly to a temperature sufficient to simultaneously sinter and densify all of the shrinking platform, the first support structure, and the part together at a uniform rate as neighboring metal particles undergo mass diffusion, and to powderize the first composite release layer to leave loose ceramic powder between the opposing surfaces, wherein the loose ceramic powder adjacent the model material surface of the part separates the part from the first support structure and allows the part to be readily removed from the first support structure after sintering.

11 . The method according to claim 10 , wherein the first binder includes a first component and a second component, and wherein the method further comprises:
resisting, with the first component, deformation of a shape of the platform-integrating part assembly during the simultaneous debinding of the first binder and second binder; and resisting, with the second component, deformation of the shape of the platform-integrating part assembly caused by gravitational force during heating of the platform-integrating part assembly.

12 . The method according to claim 10 , wherein forming the shrinking platform comprises:
forming the shrinking platform to form a foundation for the first support structure, all portions of the part commonly densifying from lateral positions located to be supported by the foundation of the shrinking platform, and wherein the shrinking platform holds the part and the first support structure in relative position during densification of the model material and prevents movement of the first support structure versus the part that tends to distort the part.

13 . The method according to claim 12 , further comprising:
forming a second support structure of the model material in a location supported by the part; and forming a second composite release layer, including the dispersed ceramic powder and the second binder, intervening between the part and the second support structure, wherein the second support structure is displaced through space while continuously supported by the part during densification of the platfor

Assignees

• Markforged Inc

Inventors

• Mark Gregory Thomas

Classifications

• B22F10/47

  characterised by structural features · CPC title

• B29C64/40 Primary

  Structures for supporting 3D objects during manufacture and intended to be sacrificed after completion thereof · CPC title

• B22F3/1118

  comprising internal reinforcements · CPC title

• B29K2079/085

  Thermoplastic polyimides, e.g. polyesterimides, PEI, i.e. polyetherimides, or polyamideimides; Derivatives thereof · CPC title

• B29C64/245

  Platforms or substrates (support structures intended to be sacrificed after manufacture B29C64/40) · CPC title