Method of edge printing for use in additive manufacturing processes

Patent metadata

Field	Value
Publication number	US-11919233-B2
Application number	US-202217889852-A
Country	US
Kind code	B2
Filing date	Aug 17, 2022
Priority date	Aug 27, 2021
Publication date	Mar 5, 2024
Grant date	Mar 5, 2024

Abstract

Various embodiments provide a method of additively manufacturing a part including depositing a layer of a powder on a working surface, depositing a binder solution on the layer of the powder at first locations, and depositing a sintering aid solution on the layer of the powder at second locations. The sintering aid solution comprises a sintering aid in a solvent. In various embodiments, the sintering aid enables an increased brown strength as compared to parts containing unbound powder. The method enables binders that provide high green strength to be used at the edges of the part, while also balancing a shortened debind time with an increased brown strength. Embodiments in which binder solution is deposited according to a predetermined pattern at second locations are also described.

First claim

What is claimed is:

1. A method of additively manufacturing a part, the method comprising:
depositing a layer of a powder on a working surface;
depositing a binder on the layer of the powder at first locations, wherein the binder comprises, based on a total weight of the binder:
greater than or equal to 93 wt % and less than or equal to 99.8 wt % of a monomer;
greater than or equal to 0.1 wt % and less than or equal to 2 wt % of a thermal initiator; and
greater than or equal to 0.1 wt % and less than or equal to 3 wt % of at least one of a super acid generating initiator, a photo-thermal initiator, and a photoinitiator; and

depositing a sintering aid solution on the layer of the powder at second locations, wherein the sintering aid solution comprises a sintering aid in a solvent.

2. The method of additively manufacturing a part of claim 1 , wherein the sintering aid comprises a fugitive metal precursor, metallic nanoparticles, ceramic nanoparticles, or combinations thereof.

3. The method of additively manufacturing a part of claim 1 , wherein the sintering aid solution is free of polymers.

4. The method of additively manufacturing a part of claim 1 , wherein the binder is deposited with a first print head and the sintering aid solution is deposited with a second print head.

5. The method of additively manufacturing a part of claim 1 , wherein the first locations correspond to a surface of the part.

6. The method of additively manufacturing a part of claim 1 , wherein the second locations correspond to a thickness of the part between surfaces of the part.

7. The method of additively manufacturing a part of claim 1 , wherein depositing the sintering aid solution on the layer comprises selectively depositing the sintering aid solution in a predetermined pattern on the layer.

8. The method of additively manufacturing a part of claim 1 , wherein depositing the sintering aid solution comprises spraying the sintering aid solution on the layer.

9. The method of additively manufacturing a part of claim 1 , further comprising:
polymerizing the binder to form a green body part having a green body strength greater than or equal to 15 MPa, as measured in accordance with ASTM B312-14; and
heat treating the green body part to remove the binder to form a brown body part having a brown body strength of greater than 1-3 MPa, as measured in accordance with ASTM B312-14.

10. The method of additively manufacturing a part of claim 9 , wherein the green body part has a green body strength greater than or equal to 20 MPa, as measured in accordance with ASTM B312-14.

11. A method of additively manufacturing a part, the method comprising:
for each of a plurality of regions of the part, determining a thickness of the part within the region, wherein the thickness of the part within each region comprises a solid wall devoid of cavities between a first surface of the region and a second surface of the region, and the thickness is a distance between the first surface and the second surface;
depositing the binder solution within a powder bed at locations corresponding to the first surface and the second surface of each of the plurality of regions to bind powder along each of the first surface and the second surface, thereby defining a geometry of the part;
for at least one of the plurality of regions of the part, depositing the binder solution within the powder bed in a predetermined pattern at locations between the first surface and the second surface such that at least some powder between the first surface and the second surface is unbound;
removing loose powder external to the geometry of the part, thereby exposing a green body part having unbound powder contained within the geometry of the part; and
sintering the green body part to generate the part, wherein the unbound powder contained in the green body part is sintered to solidify the solid wall of the part.

12. The method of claim 11 , wherein the depositing the binder solution at locations corresponding to the first surface and the second surface of each of the plurality of regions comprises depositing the binder solution at locations effective to bind a layer having a thickness of from 2.5 mm to 4.0 mm for each of the first surface and the second surface of each of the plurality of regions.

13. The method of claim 11 , wherein the predetermined pattern is selected based on processes to which the green body part will be subjected, handling to which the green body part will be subjected, loads to which the green body part will be subjected, or combinations thereof.

14. The method of claim 11 , wherein, for at least one of the plurality of regions of the part, no binder solution is deposited at locations between the first surface and the second surface such that the powder between the first surface and the second surface is unbound.

15. The method of claim 11 , wherein for at least one of the plurality of regions of the part, depositing the binder solution within the powder bed between the first surface and the second surface to bind powder between the first surface and the second surface such that substantially all of the powder between the first surface and the second surface is bound within the at least one of the plurality of regions.

16. The method of claim 11 , wherein the predetermined pattern comprises treads extending between the first surface and the second surface.

17. The method of claim 11 , wherein an amount of binder present at a surface of the green body part is greater than an amount of binder present within a thickness of a wall of the green body part.

18. The method of claim 11 , further comprising:
curing the green body part, wherein a time to cure the green body part is less than a time to cure a comparative green body part having a geometry identical to the green body part and in which all powder within the geometry of the part is bound.

Assignees

• Gen Electric

Inventors

• Thompson Mary Kathryn
• Natarajan Arunkumar
• Chan Kwok Pong
• Bromberg Vadim
• Yang Xi
• Barua Ananda
• Alberts William C

Classifications

• B29C64/165 Primary

  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

• B29C64/209

  Heads; Nozzles · CPC title

• B29C64/336

  of two or more materials · CPC title

• B33Y10/00

  Processes of additive manufacturing · CPC title

• B29K2105/0002

  monomers or prepolymers · CPC title