Supports for sintering additively manufactured parts

Patent metadata

Field	Value
Publication number	US-10052815-B2
Application number	US-201815892733-A
Country	US
Kind code	B2
Filing date	Feb 9, 2018
Priority date	Dec 2, 2016
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

Abstract

A method comprising depositing a part from layers of model material including sinterable metal particles and a first binder, the part surrounding a hole, depositing a first support structure from layers of the model material within the hole, depositing a first release layer of a release material above the first support structure and within the hole, the release material including a dispersed ceramic powder and a second binder, depositing a second release layer of a release material below the first support structure and within the hole, and forming a multipiece assembly of the part, the first and second release layers, and the first support structure, wherein, during sintering, the part and first support structure are configured to densify as a whole at a uniform rate, the release material is configured to reduce to a loose ceramic powder, and the first support structure is configured to prevent distortion of the hole.

First claim

What is claimed is:

1. A method of fabricating an additively manufactured part, comprising:
depositing a part from successive layers of model material including sinterable metal particles and a first binder, the part surrounding a hole formed therein;
depositing a first support structure from successive layers of the model material within the hole;
depositing a first release layer of a release material above the first support structure and within the hole formed in the part, the release material including a dispersed ceramic powder and a second binder;
depositing a second release layer of a release material below the first support structure and within the hole formed in the part; and
forming a multipiece assembly of the part, the first and second release layers, and the first support structure, wherein the multipiece assembly is configured to be debound as a whole, wherein the part and first support structure are configured, during sintering, to densify as a whole at a uniform rate, wherein the release material is configured, during sintering, to reduce to a loose ceramic powder that is configured to release the first support structure from the hole, and wherein the first support structure is configured to prevent a shape of the hole formed in the part from distorting from gravitational force during sintering.

2. The method according to claim 1 , further comprising:
forming, in the first support structure, a separation clearance dividing the first support structure to be separable along the separation clearance.

3. The method according to claim 2 , further comprising:
debinding the multipiece assembly as a whole in a same chamber to simultaneously remove binder components from the first binder and the second binder;
heating the multipiece assembly as a whole in a same chamber to sinter and densify the part and first support structure at a rate uniform throughout the multipiece assembly and to powderize the first release layer and the second release layer to leave loose ceramic powder between the hole formed in the part and the first support structure, wherein the first support structure is carried through space while continuously supported by walls of the hole in the part during densification of the multipiece assembly;
separating the first support structure into fragments along the separation clearance; and
releasing the fragments from the part at the first release layer and second release layer.

4. The method according to claim 3 , wherein the hole formed in the part includes a cavity having a constricted exit path, and wherein the fragments are sufficiently small to pass through the constricted exit path when released from the part.

5. The method according to claim 1 , wherein depositing the first release layer comprises forming the first release layer to intervene at a non-horizontal surface of the hole formed in the part opposing the first support structure, the non-horizontal surface of the hole formed in the part including at least one of a vertical surface, a curved surface, and a surface angled with respect to horizontal.

6. The method according to claim 1 , further comprising:
providing a shrinking platform of the model material below the part and as part of the multipiece assembly, such that the part, first support structure, and shrinking platform are configured to be debound and heated as a whole to densify the model material at a uniform rate and powderize the first and second release layers.

7. The method according to claim 6 , further comprising:
depositing a second support structure of the model material in a location supporting the part; and
depositing a second release layer, including the release material, intervening between the part and the second support structure, wherein the second release layer is configured to powderize during sintering to leave a loose ceramic powder that releases the second support structure from the part after sintering.

8. The method according to claim 6 , further comprising:
forming a third release layer intervening between a surface of the part and a top surface of the shrinking platform; and
depositing a lowermost portion of the part from successive layers of the model material directly upon the third release layer and directly opposing the top surface of the shrinking platform.

9. The method according to claim 6 , wherein providing the shrinking platform comprises forming the shrinking platform to form a foundation for the first support structure, all portions of the part configured to commonly densify from lateral positions located to be supported by the foundation of the shrinking platform, wherein the shrinking platform is configured to hold the part and the second support structure in relative position during densification of the model material and to prevent movement of the second support structure versus the part that tends to distort the part.

10. The method according to claim 6 , further comprising:
providing a sliding release layer below a bottom surface of the shrinking platform, the sliding release layer including a dispersed ceramic powder, wherein the dispersed ceramic powder adjacent the model material surface of the shrinking platform is configured to promote sliding at the bottom surface of the shrinking platform during sintering to reduce distortion.

11. A method of fabricating an additively manufactured part, comprising:
depositing a part from successive layers of model material including sinterable metal particles and a first binder;
depositing a first support structure from successive layers of the model material below the part;
forming, in the first support structure, a separation clearance dividing the first support structure to be separable along the separation clearance;
depositing a first release layer of a release material above the first support structure, the release material including a dispersed ceramic powder and a second binder; and
forming a multipiece assembly of the part, first release layer, and first support structure, wherein the multipiece assembly is configured, before sintering, to be debound as a whole, wherein the part and first support structure are configured, during sintering, to densify as a whole at a uniform rate, wherein the release material is configured, during sintering, to reduce to a loose ceramic powder configured to release the part from the first support structure, wherein the first support structure is configured, during sintering, to prevent the part from distorting from gravitational force, and wherein the first support structure is configured, following sintering, to be separated into fragments along the separation clearance.

12. The method according to claim 11 , wherein depositing the part comprises depositing the part to surround a hole formed therein, and wherein the method further comprises:
depositing a second support structure from successive layers of the model material within the hole;
depositing a second release layer of the release material above the second support structure and within the hole formed in the part; and
depositing a third release layer of the release material below the second support structure and within the hole formed in the part, wherein the multipiece assembly includes the second and third release layers and the second support structure, wherein the multipiece assembly is configured to be debound as a whole, wherein the release material is configured, during sintering, to reduce to a loose ceramic powder that is configured to release the second support structure from the hole, and wherein the second support structure is configured to prevent a shape of the hole formed in the part from distorting from gravitational

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

• B29C64/165

  using a combination of solid and fluid materials, e.g. a powder selectively bound by a liquid binder, catalyst, inhibitor or energy absorber · CPC title

• B33Y10/00

  Processes of additive manufacturing · CPC title