Binder compositions for additive manufacturing comprising low molecular weight polymers including acrylic acid repeat units

Patent metadata

Field	Value
Publication number	US-2021138550-A1
Application number	US-202017075355-A
Country	US
Kind code	A1
Filing date	Oct 20, 2020
Priority date	Oct 21, 2019
Publication date	May 13, 2021
Grant date	—

Abstract

Methods of additive manufacturing, binder compositions for additive manufacturing, and articles produced by and/or associated with methods of additive manufacturing are generally described.

First claim

1 . A method of additive manufacturing a metal-based composite structure by binder jet printing, the method comprising:
depositing a first layer of metal powder, the metal powder comprising steel; depositing a binder composition on at least a portion of the first layer of metal powder, the binder composition comprising water and a low molecular weight polymer including an acrylic acid repeat unit, wherein the binder composition has a pH of greater than or equal to 4; and drying and/or cross-linking at least the binder composition deposited on the first layer of the metal powder, thereby forming a metal-based composite structure.

2 . (canceled)

3 . The method of claim 1 , wherein the low molecular weight polymer has a weight average molecular weight of less than or equal to 40 kDa.

4 . (canceled)

5 . The method of claim 1 , wherein the metal-based composite structure has a flexural strength of greater than or equal to 2 MPa.

6 . The method of claim 5 , wherein the flexural strength is that measured by a three-point bending test.

7 . The method of claim 5 , wherein the flexural strength is that measured by a four-point bending test.

8 . The method of claim 1 , wherein the binder composition has a viscosity of less than or equal to 20 cP at a printing temperature.

9 . The method of claim 1 , wherein the wt % of the low molecular weight polymer in the binder composition is greater than or equal to 1 wt % and less than or equal to 40 wt %.

10 . (canceled)

11 . The method of claim 1 , wherein the depositing step comprises thermally depositing the binder composition, and wherein the viscosity of the binder composition is greater than or equal to 1 cP and less than or equal to 10 cP at a printing temperature.

12 . The method of claim 1 , wherein the depositing step comprises piezoelectrically depositing the binder composition, and wherein the viscosity of the binder composition is greater than or equal to 3 cP and less than or equal to 30 cP at a printing temperature.

13 . The method of claim 1 , wherein the metal powder comprises a ferrous alloy having a chromium content of less than or equal to 2 wt %, and wherein the pH of the binder composition is greater than or equal to 7.

14 . The method of claim 1 , wherein the metal powder comprises a ferrous alloy having a chromium content of greater than or equal to 2 wt %, and wherein the pH of the binder composition is greater than or equal to 4.

15 . The method of claim 1 , comprising cross-linking the binder composition using heat, UV light, and/or microwave radiation.

16 . The method of claim 1 , further comprising depositing a second layer of metal powder on the first layer of metal powder after the binder composition has been deposited thereon and prior to drying or cross-linking the binder composition deposited on the first layer of the metal powder.

17 . The method of claim 16 , further comprising depositing the binder composition on at least a portion of the second layer of metal powder prior to drying or cross-linking the binder composition deposited on the first layer of the metal powder.

18 . The method of claim 1 , further comprising depositing a second layer of metal powder on the first layer of metal powder after drying and/or cross-linking the binder composition deposited on the first layer of the metal powder.

19 . The method of claim 18 , further comprising depositing the binder composition on at least a portion of the second layer of metal powder.

20 . (canceled)

21 . The method of claim 1 , further comprising
heating the metal-based composite structure in an environment having a temperature of greater than or equal to 700° C. and less than or equal to 1400° C.

22 - 61 . (canceled)

62 . A metal-based composite structure formed by additive manufacturing, the metal-based composite structure comprising:
a metal powder comprising steel, wherein the wt % of the metal powder in the metal-based composite structure is between 92 wt % and 99.9 wt %; and a binder, wherein the binder comprises a low molecular weight polymer including an acrylic acid repeat unit.

63 . (canceled)

64 . The metal-based composite structure formed by additive manufacturing of claim 62 , wherein the low molecular weight polymer has a weight average molecular weight of less than or equal to 40 kDa.

65 - 69 . (canceled)

70 . The metal-based composite structure formed by additive manufacturing of claim 62 , wherein the binder comprises a cross-linking agent and/or a reaction product of a cross-linking agent.

71 - 72 . (canceled)

Assignees

• Desktop Metal Inc

Inventors

• Renner Christopher Benjamin
• Rushkin Ilya L
• Sachs Emanuel M

Classifications

• B22F1/10

  Metallic powder containing lubricating or binding agents; Metallic powder containing organic material · CPC title

• B33Y70/00 Primary

  Materials specially adapted for additive manufacturing · CPC title

• B22F10/14 Primary

  by jetting of binder onto a bed of metal powder · CPC title

• C22C38/18

  containing chromium · CPC title

• C22C38/00

  Ferrous alloys, e.g. steel alloys (cast-iron alloys C22C37/00) · CPC title