Decomposing polymer binders for additive manufacturing feedstock

Patent metadata

Field	Value
Publication number	US-2018162048-A1
Application number	US-201715842806-A
Country	US
Kind code	A1
Filing date	Dec 14, 2017
Priority date	Dec 14, 2016
Publication date	Jun 14, 2018
Grant date	—

Abstract

Techniques and compositions are disclosed for feedstocks with powder/binder systems for three-dimensional printing, such as fused filament fabrication. For example, a feedstock may include a primary binder and a secondary binder for supporting a shape of a three-dimensional object through processing into a final part. The primary binder may include a high molecular weight polymer useful to achieve high print quality and strength of the three-dimensional object in initial processing. Further, the high molecular weight polymer may be chemically decomposed, and thus rapidly debound from the three-dimensional object, through exposure to a solvent. The secondary binder may be substantially insoluble in the solvent such that the secondary binder may remain to support a net shape of the three-dimensional object in subsequent processing. Accordingly, the high molecular weight polymer in the primary binder, in combination with the second binder, may be useful for rapid three-dimensional manufacturing of high quality parts.

First claim

What is claimed is:

1 . A method of additive manufacturing, the method comprising:
moving one or more nozzles along an extrusion path relative to a build plate; extruding a feedstock through the one or more nozzles, the feedstock including a binder system and a powder material dispersed in the binder system, the extrusion of the feedstock forming a three-dimensional object along the extrusion path; exposing the three-dimensional object to a chemical solution, the chemical solution chemically decomposing a polymer of a primary binder of the binder system, and the chemical decomposition of the polymer occurs during a chemical dissolution of at least a portion of the primary binder from the three-dimensional object as a secondary binder of the binder system supports a shape of the three-dimensional object; debinding the secondary binder from the three-dimensional object; and densifying the powder material in the three-dimensional object to form a final part.

2 . The method of claim 1 , wherein the secondary binder is substantially insoluble in the chemical solution to which the three-dimensional object is exposed.

3 . The method of claim 1 , wherein the polymer of the primary binder is a high molecular weight polymer.

4 . The method of claim 3 , wherein the high molecular weight polymer of the primary binder has a molecular weight of greater than about 100,000 g/mol.

5 . The method of claim 3 , wherein the secondary binder includes a second polymer, and the second polymer has a molecular weight less than or about equal to a molecular weight of the high molecular weight polymer.

6 . The method of claim 1 , wherein the powder material includes one or more of a metal, a metal alloy, or a ceramic.

7 . The method of claim 1 , wherein the primary binder further includes a wax soluble in the chemical solution as the three-dimensional object is exposed to the chemical solution.

8 . The method of claim 1 , wherein the primary binder is debound from the three-dimensional object leaving a waste stream including aqueous monosaccharides.

9 . The method of claim 1 , wherein densifying the powder includes one or more of sintering the three-dimensional object or infiltrating the three-dimensional object with a liquid metal.

10 . A feedstock for additive manufacturing, the feedstock comprising:
a powder material; a primary binder containing a high molecular weight polymer chemically decomposable and dissoluble upon exposure to a chemical solution; and a secondary binder for retaining, during a thermal process, a shape of a part formed from the feedstock, the secondary binder substantially insoluble in the chemical solution with which the high molecular weight polymer is depolymerizable.

11 . The feedstock of claim 10 , wherein the high molecular weight polymer has a molecular weight of greater than about 100,000 g/mol.

12 . The feedstock of claim 10 , wherein the chemical solution comprises a catalyst to for the chemical decomposition of the high molecular weight polymer.

13 . The feedstock of claim 12 , wherein the chemical decomposition occurs via depolymerization.

14 . The feedstock of claim 10 , wherein the high molecular weight polymer of the primary binder includes at least one of a thermoplastic polysaccharide, polylactic acid, polyglycolic acid, poly(lactide)-co-(caprolactone), copolymers containing styrene blocks, polyethylene glycol, PEG-PMMA, a urethane ester, and a polyanhydride.

15 . The feedstock of claim 10 , wherein the high molecular weight polymer is chemically decomposable in one or more of an aqueous solution or an alkaline solution.

16 . The feedstock of claim 10 , wherein the chemical solution is an aqueous solution and the high molecular weight polymer is hydrolysable in the aqueous solution.

17 . The feedstock of claim 10 , wherein the high molecular weight polymer is chemically decomposable in an acidic solution.

18 . A three-dimensional object comprising:
a plurality of layers collectively forming the three-dimensional object, each layer coupled to at least one other layer, and each layer including a powder material, a primary binder containing a high molecular weight polymer chemically decomposable and dissoluble with a chemical solution, and a secondary binder for retaining, during a thermal process, a shape of the three-dimensional object, the secondary binder substantially insoluble in the chemical solution with which the high molecular weight polymer is chemically decomposable.

19 . The three-dimensional object of claim 18 , wherein the high molecular weight polymer has a molecular with of greater than about 100,000 g/mol.

20 . The three-dimensional object of claim 18 , wherein the secondary binder includes a second polymer, and the second polymer has a molecular weight less than about equal to a molecular weight of the high molecular weight polymer.

Assignees

• Desktop Metal Inc

Inventors

• Gibson Michael Andrew
• Barbati Alexander C

Classifications

• B22F12/10

  Auxiliary heating means · CPC title

• B22F10/12

  by photopolymerisation, e.g. stereolithography [SLA] or digital light processing [DLP] · CPC title

• B22F12/55

  Two or more means for feeding material · CPC title

• B22F12/86

  Serial processing with multiple devices grouped · CPC title

• B22F10/28

  Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM] · CPC title