Supports for sintering additively manufactured parts

Patent metadata

Field	Value
Publication number	US-10040241-B2
Application number	US-201815892741-A
Country	US
Kind code	B2
Filing date	Feb 9, 2018
Priority date	Dec 2, 2016
Publication date	Aug 7, 2018
Grant date	Aug 7, 2018

Abstract

A method comprising forming a shrinking platform of layers of a composite, the composite including a metal particulate filler in a first matrix, forming a shrinking support of layers of the composite upon the shrinking platform, forming a first release layer of a release material upon the shrinking support, the release material including a ceramic particulate and a second matrix, and forming a part of the composite upon the shrinking support to form a portable assembly from the combined shrinking platform, shrinking support, release layer and part, wherein substantially horizontal portions of the part are vertically supported by the shrinking platform, wherein the first release layer is configured, after sintering, to separate the part from the shrinking support and to allow the part to be readily removed from the shrinking support, and wherein the shrinking support is configured to prevent the part from distorting 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 successive layers of a composite, the composite including a metal particulate filler in a first matrix;
forming a shrinking support of successive layers of the composite upon the shrinking platform;
forming a first release layer of a release material upon the shrinking support, the release material including a ceramic particulate and a second matrix; and
forming a part of the composite upon the shrinking support to form a portable assembly from the combined shrinking platform, shrinking support, release layer and part that is configured to be transported, debound, and sintered as a unit, wherein substantially horizontal portions of the part are vertically supported by the shrinking platform, wherein the first release layer is configured, after sintering, to separate the part from the shrinking support and to allow the part to be readily removed from the shrinking support, and wherein the shrinking support is configured to prevent the part from distorting from gravitational force during sintering.

2. The method according to claim 1 , further comprising:
depositing an open cell structure in at least one of the shrinking platform, the shrinking support, and the part; and
penetrating a fluid debinder into the open cell structure to debind at least one of the first matrix and the second matrix from within the open cell structure.

3. The method according to claim 1 , wherein forming the first release layer comprises forming the first release layer to intervene at a non-horizontal surface of the part opposing a surface of the shrinking support, 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.

4. The method according to claim 1 , wherein the first binder includes a first component and a second component, and further comprising:
resisting, with the first component, deformation of the shape of the portable assembly during the simultaneous debinding of the first matrix and second matrix; and
resisting, with the second component, deformation of the shape of the brown portable assembly caused by gravitational force.

5. The method according to claim 1 , further comprising:
forming a lateral support shell of the composite following a lateral contour of the part; and
connecting the lateral support shell to the lateral contour of the part by forming separable attachment protrusions of the composite between the lateral support shell and the part.

6. The method according to claim 1 , further comprising:
forming soluble support structures that resist downward forces during the forming of the part; and
dissolving the soluble support structures before heating the brown portable assembly.

7. The method according to claim 1 , further comprising:
forming soluble support structures of the release material that resist downward forces during the forming of the part; and
debinding the second matrix to dissolve the second matrix of the soluble support structures and leave loose ceramic particulate before heating the brown portable assembly.

8. The method according to claim 1 , further comprising:
providing a sliding powder layer below the shrinking platform, of equal or larger surface area than a bottom of the shrinking platform, that reduces lateral resistance between the shrinking platform and an underlying surface;
simultaneously, and in a same chamber, debinding a component of the first matrix and of the second matrix in the portable assembly to form a brown portable assembly; and
heating the brown portable assembly to shrink all of the shrinking platform, the shrinking support, and the part together at a same rate as neighboring metal particles throughout the shape-retaining brown part assembly undergo atomic diffusion.

9. The method according to claim 8 , wherein the underlying surface comprises a portable build plate, wherein forming the shrinking platform comprises forming the shrinking platform above the portable build plate, wherein providing the sliding powder layer comprises forming the sliding powder layer below the shrinking platform and above the portable build plate with the release material, and wherein the method further comprises:
keeping the portable assembly together as a unit during the debinding;
sintering the brown portable assembly during the heating; and
keeping the brown portable assembly together during sintering, and after sintering, separating the build plate, sliding powder layer, shrinking platform, first release layer and shrinking support from the part.

10. The method according to claim 8 , further comprising:
powderizing the first release layer during the heating to leave loose ceramic powder between the opposing surfaces.

11. The method according to claim 1 , wherein forming the shrinking platform comprises forming the shrinking platform to form a foundation for the shrinking support, all portions of the part configured to commonly shrink from lateral positions located to be supported by the foundation of the shrinking platform, and wherein the shrinking platform is configured to hold the part and the shrinking support in relative position during shrinking of the same composite and to prevent movement of the shrinking support versus the part that tends to distort the part.

12. The method according to claim 11 , further comprising:
forming an interior support structure of the composite in a location supported by the part; and
forming a second release layer of the release material intervening between the part and the interior support structure, wherein the second support structure is configured to be displaced through space while continuously supported by the part during shrinking of the brown portable assembly, and the second release layer is configured to powderize during the heating to leave a loose powder that allows the interior support structure to be readily removed from the part after sintering.

13. The method according to claim 12 , further comprising:
forming a third release layer of the release material intervening between a surface of the part and a top surface of the shrinking platform; and
forming a lowermost portion of the part from successive layers of the composite directly upon the third release layer and directly opposing the top surface of the shrinking platform.

14. The method according to claim 11 , further comprising:
interconnecting the composite of the shrinking platform to the composite of the shrinking support to permit mass diffusion between neighboring metal particles found in the shrinking platform adjacent metal particles found in the shrinking support, to unitarily shrink the shrinking platform and the shrinking support.

15. The method according to claim 1 , wherein the metal particulate filler includes metal particles distributed in a range of sizes.

16. A method of reducing distortion in an additively manufactured part; comprising:
depositing a shrinking platform of successive layers of a composite, the composite including a metal particulate filler in a first matrix;
depositing a plurality of shrinking supports of successive layers of the composite upon the shrinking platform;
interconnecting the composite of the shrinking platform to the plurality of shrinking supports to permit mass diffusion between neighboring metal particles found in the shrinking platform that are adjacent to metal particles found in the plurality of shrinking supports, to unitarily shrink the shrinking platform an

Assignees

• Markforged Inc

Inventors

• Mark Gregory Thomas

Classifications

• B29C64/40 Primary

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

• B22F10/47

  characterised by structural features · CPC title

• B29K2079/085

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

• B22F3/1118

  comprising internal reinforcements · CPC title

• B29C70/16

  using fibres of substantial or continuous length {(non-woven fabrics per se D04H3/00)} · CPC title