3d printing internal free space

Patent metadata

Field	Value
Publication number	US-2019047047-A1
Application number	US-201816165291-A
Country	US
Kind code	A1
Filing date	Oct 19, 2018
Priority date	Dec 2, 2016
Publication date	Feb 14, 2019
Grant date	—

Abstract

For 3D printing green parts to be debound and sintered, a binder may be jetted into successive layers of sinterable powder feedstock to build up a 3D shape of a desired 3D green part, associated sintering supports, and an associated shrinking platform. A release material may be deposited to intervene between the 3D green parts and the sintering supports. A placeholder material may be deposited upon bound powder to form 2D layer shapes of placeholder material, and the sinterable powder feedstock refilled and leveled about the placeholder material. Upon debinding, internal cavities corresponding to the 3D shapes of the placeholder material are formed.

First claim

What is claimed is:

1 . A method for 3D printing green parts, comprising:
jetting a binder onto successive layers of powder feedstock in a powder bed to form a 2D layer shape of bound powder per layer; building up a 3D shape of a first desired 3D green part from interconnected 2D layer shapes of the bound powder; building up a 3D shape of sintering supports from interconnected 2D layer shapes of the bound powder; building up a 3D shape of a shrinking platform from interconnected 2D layer shapes of the bound powder; and forming a green part assembly including the first desired 3D green part, the sintering supports, and the shrinking platform.

2 . The method of claim 1 , further comprising applying a release material upon shapes of bound powder to form a 2D layer shape of release material.

3 . The method of claim 2 , further comprising:
building up a 3D shape of a release surface from interconnected 2D layer shapes of the release material, wherein forming the green part assembly includes forming the green part assembly including the release surface.

4 . The method of claim 2 , wherein applying the release material includes applying the release material to form a complementary 2D layer shape intervening between a sintering support and the first desired 3D green part.

5 . The method of claim 1 , further comprising applying a placeholder material upon shapes of bound powder to form a 2D layer shape of placeholder material.

6 . The method of claim 5 , further comprising:
building up a 3D shape of placeholder volumes from interconnected 2D layer shapes of the placeholder material, wherein forming the green part assembly includes forming the green part assembly including an internal cavity corresponding to the 3D shape of the placeholder material.

7 . The method of claim 5 , wherein applying the placeholder material includes applying the placeholder material to form a complementary 2D layer shape of desired free space within the desired part or the sintering supports.

8 . The method of claim 5 , wherein applying the placeholder material includes applying the placeholder material to form a 2D layer shape of a shell, the shell capturing unbound powder feedstock within.

9 . The method of claim 8 , wherein jetting the binder includes jetting the binder onto the powder feedstock within the shell to form a reinforcement shape within the shell.

10 . The method of claim 5 , wherein applying the placeholder material includes applying the placeholder material to form a complementary 2D layer shape of adhesive between the shrinking platform and an underlying build platform.

11 . The method of claim 5 , wherein applying the placeholder material includes applying the placeholder material to form a complementary 2D layer shape of adhesive on the first desired 3D green part.

12 . The method of claim 11 , further comprising building up a 3D shape of a second desired 3D green part from interconnected 2D layer shapes of the bound powder, the second desired 3D green part stacked on the complementary 2D layer shape of adhesive on the first desired 3D green part.

13 . The method of claim 1 , wherein jetting includes jetting the binder onto successive layers of one of sinterable powder feedstock and ceramic powder feedstock to form the 2D layer shape of bound powder per layer.

14 . The method of claim 1 , further comprising refilling the powder bed with new or recycled powder feedstock with each successive layer.

15 . The method of claim 14 , further comprising leveling the refilled powder feedstock with a powder leveling mechanism for each successive layer.

16 . The method of claim 14 , further comprising shaping one of the 2D layer shapes of bound powder with a surface finishing mechanism prior to refilling the powder bed.

17 . The method of claim 1 , wherein jetting includes adjusting an amount of binder jetted onto a layer of the powder feedstock based on whether an outer portion of the 2D layer shape or an inner portion of the 2D layer shape is being formed.

18 . The method of claim 1 , further comprising:
removing the green part assembly from the powder feedstock in the powder bed; and removing unbound power from the green part assembly.

19 . The method of claim 19 , wherein removing the unbound powder includes removing the unbound power from surroundings of the first desired 3D green part and the sintering supports via outlets formed in the bound powder.

20 . A method for 3D printing green parts, comprising:
jetting a binder onto successive layers of powder feedstock in a powder bed to form a 2D layer shape of bound powder per layer; building up a 3D shape of a desired 3D green part from interconnected 2D layer shapes of the bound powder; applying a placeholder material upon shapes of bound powder to form 2D layer shapes of placeholder material; building up a 3D shape of placeholder volumes from interconnected 2D layer shapes of the placeholder material; and forming a green part assembly including the desired 3D green part and a cavity corresponding to the 3D shape of the placeholder material.

21 . The method of claim 20 , wherein applying the placeholder material includes applying the placeholder material to form 2D layer shapes of a shell, the shell surrounding the cavity.

22 . The method of claim 20 , wherein forming the 2D layer shapes of the shell includes capturing unbound powder feedstock within the shell.

23 . The method of claim 22 , wherein jetting the binder includes jetting the binder onto the powder feedstock within the shell to form a reinforcement shape within the shell.

24 . The method of claim 20 , further comprising removing the unbound power from surroundings of the desired 3D green part via outlets formed in the bound powder.

25 . The method of claim 20 , wherein applying the placeholder material includes applying the placeholder material to form a 2D layer shape of a mold defining an outer skin of the desired 3D part.

26 . The method of claim 20 , wherein applying the placeholder material includes applying the placeholder material to form a complementary 2D layer shape of adhesive on an underlying build platform.

27 . The method of claim 20 , wherein applying the placeholder material includes applying the placeholder material to form a complementary 2D layer shape of adhesive on the desired 3D green part.

28 . The method of claim 20 , further comprising removing the placeholder material from the green part assembly prior to sintering the green part assembly.

29 . The method of claim 20 , further comprising sintering the green part assembly including the placeholder material.

30 . A method for 3D printing green parts, comprising:
jetting a binder onto successive layers of powder feedstock to form a 2D layer shape of bound powder per layer; building up a 3D shape of a desired 3D green part from interconnected 2D layer shapes of the bound powder; building up a 3D shape of sintering supports from interconnected 2D layer shapes of the bound powder; building up a 3D shape of a shrinking platform from interconnected 2D layer shapes of the bound powder; applying a release material upon shapes of bound powder to form 2D layer shapes of release material; building up a 3D shape of release surfaces from interconnected 2D layer shapes of the releas

Assignees

• Markforged Inc

Inventors

• Mark Gregory Thomas

Classifications

• B22F1/142

  Thermal or thermo-mechanical treatment · CPC title

• B22F10/16

  by embedding the binder within the powder bed · CPC title

• B22F10/40

  Structures for supporting workpieces or articles during manufacture and removed afterwards · CPC title

• B22F1/10

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

• B22F3/1025 Primary

  not by heating only · CPC title