Automated de-powdering with level based nesting

Patent metadata

Field	Value
Publication number	US-10406751-B2
Application number	US-201815892895-A
Country	US
Kind code	B2
Filing date	Feb 9, 2018
Priority date	Apr 14, 2017
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

A system for separating objects within a stacked powder print bed of nested objects comprises a build box configured to contain the powder print bed. The build box has a build box top and a build box floor. The system further includes an elongated aperture formed in a side wall of the build box, and a de-powdering subsystem configured to mechanically and electrically engage the build box. A separating blade associated with the de-powdering subsystem is configured to be inserted through the elongated aperture and into the powder print bed between a top-most print bed layer of the nested objects and a second print bed layer directly below and contiguous with the top-most layer, thereby forming an isolated powder print bed between the separating blade and the build box top. The unbound powder may be agitated by various techniques and subsequently removed from the objects.

First claim

What is claimed is:

1. A system for separating one or more objects within a stacked powder print bed of nested objects, comprising:
a build box configured to contain the powder print bed, the build box having a build box top and a build box floor;
at least one separating plate configured to be disposed between contiguous powder bed layers of the powder print bed; and
a de-powdering subsystem configured to mechanically and electrically engage the build box;
the at least one separating plate comprises a separating blade associated with the de-powdering subsystem, the separating blade configured to be inserted through an elongated aperture formed in a side wall of the build box and into the powder print bed between a top-most print bed layer of the nested objects and a second print bed layer directly below and contiguous with the top-most layer, thereby forming an isolated powder print bed between the separating blade and the build box top.

2. The system of claim 1 , wherein the de-powdering subsystem comprises at least one air jet device configured to agitate unbound powder within the isolated powder print bed, and at least one vacuum device configured to withdraw the agitated unbound powder from the isolated powder print bed.

3. The system of claim 2 , wherein the at least one air jet device comprises a high-volume, coarse de-powdering air jet device, and a low volume, fine de-powdering air jet device.

4. The system of claim 2 , wherein the at least one air jet device is conveyed by a robotic arm to locations within the isolated powder print bed.

5. The system of claim 4 , wherein the robotic arm is guided by a control system using information related to a surface associated with the one or more objects in a top-most layer of the powder print bed.

6. The system of claim 5 , wherein the information related to the surface is derived from a model of at least one object in the top-most layer of the powder print bed.

7. The system of claim 1 , wherein the de-powdering system further comprises a secondary agitator.

8. The system of claim 7 , wherein the secondary agitator comprises a mechanical vibration generator configured to convey mechanical vibrations to the build box.

9. The system of claim 8 , wherein the mechanical vibration generator conveys vibrations to a particular region of the powder bed within the build box.

10. The system of claim 7 , wherein the secondary agitator comprises an ultrasonic generator for conveying ultrasonic energy to a particular region of the powder bed within the build box.

11. The system of claim 1 , wherein the build box further comprises an elevator configured to raise the build box floor toward the build box top following a withdrawal of the separating blade, thereby moving the second object to a top-most position of the nested objects.

12. The system of claim 11 , wherein the de-powdering subsystem is configured to re-insert the separating blade through the elongated aperture and into the powder print bed below the second object, thereby forming the isolated powder print bed between the separating blade and the build box top.

13. The system of claim 1 , wherein the de-powdering subsystem comprises a washing device configured to convey a washing solution to one or more of the nested objects, a vacuum device configured to remove the washing solution conveyed to the one or more objects, and one or both of (i) an air jet device configured to dry the washing solution from the one or more objects and (ii) a heating device for applying a heat convection to the one or more objects, the one or more objects being printed with a binding material that is insoluble by the washing solution.

14. The system of claim 1 , further including a robotic arm configured to access and to manipulate at least one of the nested objects.

15. The system of claim 14 wherein the robotic arm is configured to remove the at least one nested object from the powder print bed.

16. The system of claim 1 , further comprising a ramp associated with the build box, wherein the ramp is configured to accommodate conveyance of at least one of the nested objects from the powder print bed to a location outside of the build box.

17. The system of claim 16 , further comprising a mechanical vibration generator configured to convey mechanical vibrations to the ramp.

18. The system of claim 16 , wherein the ramp is configured to comprise one or both of (i) at least one aperture disposed across a top surface of the ramp, the at least one aperture defining at least one void through the ramp, and (ii) a bevel along a length of the top surface of the ramp, the bevel configured to cause loose powder to be moved off the ramp.

19. The system of claim 1 , further comprising a powder collection system configured to collect unbound powder from the powder print bed, the collection system comprising at least one guiding component and at least one collection reservoir.

20. The system of claim 1 , wherein the at least one separating plate is a printed layer of bound powder, created by a binder jet printer subsystem as the powder print bed is formed.

21. The system of claim 1 , wherein the at least one separating plate is inserted between adjacent layers of the powder print bed when one or both of the adjacent layers of the powder print bed have been at least partially completed.

22. The system of claim 1 , wherein the de-powdering subsystem further comprises a bath subsystem, the bath sub system comprising:
a reservoir configured to contain a liquid and to accept objects to be de-powdered into the liquid;
an agitation facility configured to cause currents within the liquid.

23. The system of claim 22 , wherein the agitator facility comprises at least one of (i) a pump configured to circulate the liquid within the reservoir, (ii) a heating element configured to generate convection currents in the liquid, and (iii) a stirrer driven through a linkage to a motor.

24. The system of claim 22 , further comprising at least one ultrasonic transducer configured to apply ultrasonic vibrations to the liquid within the reservoir.

25. The system of claim 1 , wherein the one or more objects within the stacked powder print bed are formed using a water-fast binding agent.

26. The system of claim 25 , wherein the water-fast binding agent comprises polyacrylic acid.

27. A method of separating objects within a stacked powder bed of nested objects, comprising:
mechanically and electrically engaging a build box to a de-powdering system;
inserting, by the de-powdering subsystem, a separating blade through an aperture in a side wall of the build box and into the stacked powder bed between the a top-most object of the nested objects and a second object directly below the top-most object, so as to form an isolated powder print bed between the separating blade and a top of the build box; and
removing, by the de-powdering subsystem, unbound powder from the isolated powder print bed.

28. The method of claim 27 , wherein removing the unbound powder further comprises directing an air jet into the isolated powder print bed to agitate the unbound powder and withdrawing the agitated unbound powder with a vacuum device.

29. The method of claim 28 , further comprising directing the air jet towards the object within the isolated powder print bed using a robotic arm.

30. The method of cla

Assignees

• Desktop Metal Inc

Inventors

• Fulop Ricardo
• Shydo Robert Michael
• Myerberg Jonah Samuel
• Martin Charles Edward
• Cumming Justin
• Hoisington Paul
• Sachs Emanuel M
• Hudelson George
• Sachs Daniel
• Go Jamison
• Wong Eric
• Mccalmont Alexander K

Classifications

• B22F12/88

  Handling of additively manufactured products, e.g. by robots · CPC title

• B22F12/222

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

• B22F10/68

  Cleaning or washing · CPC title

• B22F10/14

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

• B29C64/357

  Recycling · CPC title