System and method for controlling powder bed density for 3D printing

Patent metadata

Field	Value
Publication number	US-10940533-B2
Application number	US-201816166968-A
Country	US
Kind code	B2
Filing date	Oct 22, 2018
Priority date	Dec 26, 2017
Publication date	Mar 9, 2021
Grant date	Mar 9, 2021

Abstract

A system and corresponding method for additive manufacturing of a three-dimensional (3D) object to improve packing density of a powder bed used in the manufacturing process. The system and corresponding method enable higher density packing of the powder. Such higher density packing leads to better mechanical interlocking of particles, leading to lower sintering temperatures and reduced deformation of the 3D object during sintering. An embodiment of the system comprises means for adjusting a volume of a powder metered onto a top surface of the powder bed to produce an adjusted metered volume and means for spreading the adjusted metered volume to produce a smooth volume for forming a smooth layer of the powder with controlled packing density across the top surface of the powder bed. The controlled packing density enables uniform shrinkage, without warping, of the 3D object during sintering to produce higher quality 3D printed objects.

First claim

What is claimed is:

1. A binder jet system for additive manufacturing of a three-dimensional object, the system comprising:
a hopper configured to move across a powder print bed in a direction of travel and to deposit an amount of powder material onto the powder print bed;
an adjustment apparatus positioned downstream of the hopper in the direction of travel, wherein the adjustment apparatus is configured to adjust a height of the amount of powder material on the powder print bed, wherein the adjustment apparatus includes a skimming device and at least one vacuum device spaced apart from and separate from the skimming device, wherein the skimming device is positioned downstream of the at least one vacuum device in the direction of travel;
a spreading apparatus positioned downstream of the adjustment apparatus in the direction of travel, wherein the spreading apparatus is configured to spread the amount of powder material across the powder print bed to form a layer; and
a print head positioned downstream of the spreading apparatus in the direction of travel, wherein the print head is configured to deposit a fluid to bind at least one region of the layer of powder material.

2. The system of claim 1 , wherein the adjustment apparatus is configured to remove at least a portion of the amount of powder material from the powder print bed.

3. The system of claim 2 , wherein an intended height of the powder material is predetermined and the adjustment apparatus is configured to remove at least a portion of the amount of powder material that causes the amount of powder material to exceed the predetermined height.

4. The system of claim 1 , wherein the adjustment apparatus includes a first vacuum device positioned upstream of the skimming device in the direction of travel and a second vacuum device positioned downstream of the skimming device in the direction of travel, wherein the first and second vacuum devices are configured to remove at least a portion of the amount of powder material that exceeds a target height from the powder print bed.

5. The system of claim 4 , wherein the adjustment apparatus includes a rotatable auger that is configured to direct at least a portion of the removed powder material into a container separate from the powder print bed.

6. The system of claim 5 , wherein the container is operably coupled to the hopper.

7. The system of claim 5 , wherein the powder material is a metal powder material, and wherein the container is a blender configured to blend the removed metal powder material with another amount of metal powder material.

8. The system of claim 2 , wherein the adjustment apparatus comprises a skimming device configured to skim the amount of powder material to remove at least a portion of the powder material from the powder print bed.

9. The system of claim 8 , wherein the skimming device includes a narrowed edge portion that is oriented to contact the amount of powder material to remove the at least a portion of the powder material that exceeds a target height from the powder print bed.

10. The system of claim 4 , wherein the adjustment apparatus comprises a roller configured to rotate about an axis.

11. The system of claim 10 , wherein the roller is configured to rotate about the axis in a direction such that a portion of the roller closest to the powder print bed rotates in a same direction as a direction of travel of the roller.

12. The system of claim 10 , wherein the axis of the roller is angled at a non-perpendicular angle relative to a direction of travel of the roller across the powder print bed.

13. The system of claim 1 , wherein the at least one vacuum device is configured to apply suction to the amount of powder material to remove the at least a portion of the powder material.

14. The system of claim 13 , wherein the at least one vacuum device comprises a roller with one or more vents configured to apply the suction to the amount of powder material to remove the at least a portion of the powder material through the one or more vents.

15. The system of claim 1 , further comprising a roller positioned ahead of the spreading apparatus relative to a direction of travel of the spreading apparatus across the powder print bed, wherein an axis of rotation of the roller is angled at a non-perpendicular angle relative to a direction of travel of the roller across the powder print bed.

16. The system of claim 15 , wherein the roller positioned ahead of the spreading apparatus is configured to traverse the powder print bed in the direction of travel of the spreading apparatus, and wherein the roller is configured to rotate around an axis in a direction such that a portion of the roller closest to the powder print bed rotates in a same direction as the direction of travel.

Assignees

• Desktop Metal Inc

Inventors

• Hudelson George
• Sachs Emanuel M
• Jordan Glenn A
• Zero Midnight

Classifications

• B22F10/37

  of powder bed aspects, e.g. density · CPC title

• B22F12/57

  Metering means · CPC title

• B22F12/63

  Rollers · CPC title

• B22F12/52

  Hoppers · CPC title

• B22F12/224

  for motion along a direction within the plane of a layer · CPC title