Method for dispensing of powders

• US 5,934,343 A
• Filed: 03/31/1998
• Issued: 08/10/1999
• Est. Priority Date: 03/31/1997
• Status: Expired due to Fees

• Current Assignee: Therics Inc.
• Original Assignee: Therics Inc.
• Inventors: Imiolek, Ireneusz J., Gaylo, Christopher M.
• Primary Examiner(s): Douglas, Steven O.
• Application Number:
  US09/052,179
• Time in Patent Office: 497 Days
• Field of Search: 141/12, 141/73, 141/74, 141/80, 141/280, 141/125, 264/308, 425/218, 425/253, 425/447
• US Class Current: 141/12
• CPC Class Codes: B22F 10/12 by photopolymerisation, e.g. stereolithography [SLA] or digital light processing [DLP]
• CPC Class Codes: B22F 10/14 by jetting of binder onto a bed of metal powder
• CPC Class Codes: B22F 10/28 Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 3/004 Filling molds with powder feeding material to presses in general B30B15/302
• CPC Class Codes: B29C 2791/008 Using vibrations during moulding
• CPC Class Codes: B29C 41/12 Spreading-out the material on a substrate , e.g. on the surface of a liquid
• CPC Class Codes: B29C 41/36 Feeding the material on to the mould, core or other substrate
• CPC Class Codes: B29C 64/153 using layers of powder being selectively joined, e.g. by selective laser sintering or melting
• CPC Class Codes: B29C 64/214 Doctor blades
• CPC Class Codes: B29C 64/218 Rollers
• CPC Class Codes: B29C 64/245 Platforms or substrates support structures intended to be sacrificed after manufacture B29C64/40
• CPC Class Codes: B29C 64/329 using hoppers
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B33Y 40/00 Auxiliary operations or equipment, e.g. for material handling
• CPC Class Codes: Y02P 10/25 Process efficiency

Abstract

A method and apparatus for dispensing and distributing a powder is disclosed which uses a rotary dispenser to dispense the powder by gravity onto a movable platen, the platen being movable to a position adjacent to a build bed, where the powder can be distributed across the build bed using a spreader. The method and apparatus are also suited to dispensing of a plurality of powders used in build beds for solid free-form fabrication and three dimensional printing.

Claims

1. A method for dispensing and distributing a powder, comprising the steps of:

(1) dispensing a powder by gravity feed from a hopper onto a platen, said platen being in a first platen position, where the first platen position is below said hopper;

(2) conveying said platen horizontally from the first platen position to a second platen position, where the second platen position is adjacent to a build bed;

(3) distributing said powder from said platen in the second platen position over said build bed with a spreader, said spreader moving horizontally from a first spreader position to a second spreader position to distribute said powder across said build bed;

(4) returning said spreader from the second spreader position to the first spreader position; and

(5) returning said platen to the first platen position.

2. The method of claim 1, wherein said spreader comprises a doctor blade.

3. The method of claim 2, wherein said doctor blade has a straight edge for spreading.

4. The method of claim 2, wherein said doctor blade has a curved edge for spreading.

5. The method of claim 1, wherein said spreader comprises an elongate roller for spreading.

6. The method of claim 5, wherein said roller rotates during spreading in a direction counter to the direction of horizontal motion of said roller.

7. The method of claim 1, further comprising a step (6) of compacting the spread powder in said build bed with an elongate roller which is either the spreader roller or a second roller.

8. The method of claim 7, wherein said roller vibrates while compacting said powder.

9. The method of claim 8, wherein said vibration is in a direction essentially orthogonal to a surface of said powder.

10. The method of claim 1, wherein said dispensing is carried out using a rotary dispenser disposed at the bottom of said hopper.

11. The method of claim 10, wherein said rotary dispenser comprises a cylindrical sleeve having a long axis and two opposed side openings parallel to the long axis, having a first opposed side open to an interior of said hopper and having a second opposed side open to an exterior of said hopper, said rotary dispenser further comprising a cylinder sized and shaped to be closely received within said cylindrical sleeve and rotatably mounted within said cylindrical sleeve, said cylinder further having an elongate recess disposed at the surface of said cylinder.

12. A method for dispensing and distributing a plurality of powders, comprising the steps of:

(1) dispensing a selected powder by gravity feed from a selected powder containing hopper onto a platen, said platen being in a first platen position below said hopper, where said hopper is selected from a plurality of powder containing hoppers;

(2) conveying said platen horizontally along a conveying means from the first platen position to a second platen position, said second platen position selected along said conveying means such that the selected powder on said platen is adjacent to said build bed;

(3) distributing said powder from said platen in the second platen position to said build bed with a spreader, said spreader moving horizontally from a first spreader position to a second spreader position to distribute said powder across said build bed;

(4) returning said spreader from the second spreader position to the first spreader position;

(5) returning said platen from the second platen position to the first platen position; and

(6) repeating steps (1), (2), (3), (4) and (5) a selected number of times wherein the powder and the hopper used in each repetition is independently selected.

13. The method of claim 12, wherein said spreader comprises a doctor blade.

14. The method of claim 13, wherein said doctor blade has a straight edge for spreading.

15. The method of claim 13, wherein said doctor blade has a curved edge for spreading.

16. The method of claim 12, wherein said spreader comprises an elongate roller for spreading.

17. The method of claim 16, wherein said roller rotates during spreading in a direction counter to the direction of horizontal motion of said roller.

18. The method of claim 12, further comprising a step (6) of compacting the spread powder in said build bed with an elongate roller which is either the spreader roller or a second roller.

19. The method of claim 18, wherein said roller vibrates while compacting said powder.

20. The method of claim 19, wherein said vibration is in a direction essentially orthogonal to a surface of said powder.

21. The method of claim 12, wherein said dispensing is carried out using a rotary dispenser disposed at the bottom of said hopper.

22. The method of claim 21, wherein said rotary dispenser comprises a cylindrical sleeve having a long axis and two opposed side openings parallel to the long axis, having a first opposed side open to an interior of said hopper and having a second opposed side open to an exterior of said hopper, said rotary dispenser further comprising a cylinder sized and shaped to be closely received within said cylindrical sleeve and rotatably mounted within said cylindrical sleeve, said cylinder further having an elongate recess disposed at the surface of said cylinder.

23. An apparatus for dispensing and distributing powder, comprising:

a) a hopper for containing a powder to be dispensed;

b) a rotary dispenser for measuring and dispensing a volume of the powder, said rotary dispenser being mounted horizontally at the bottom of said hopper, and comprising a cylindrical sleeve having a long axis and two opposed side openings parallel to the long axis, having a first opposed side open to an interior of said hopper and having a second opposed side open to an exterior of said hopper, said rotary dispenser further comprising a cylinder sized and shaped to be closely received within said cylindrical sleeve and rotatably mounted within said cylindrical sleeve, said cylinder further having an elongate recess disposed along a surface of said cylinder.

c) means for rotating said cylinder from a first cylinder position, having the recess open to the interior of said hopper, to a second cylinder position, having the recess open to the exterior of said hopper;

d) a platen for carrying the powder, said platen disposed horizontally below said hopper and mounted for linear motion along a first axis from a first platen position below and adjacent to said hopper, to a second platen position adjacent to a build bed;

e) means for distributing the powder from said platen in the second platen position, over said build bed, said distribution means mounted for linear motion along a second axis generally orthogonal to the first axis.

24. The apparatus of claim 23, wherein said means for rotating comprises a rotating crank.

25. The apparatus of claim 24, wherein said rotating crank is motor driven.

26. The apparatus of claim 25, wherein said distribution means comprises an elongate roller.

27. The apparatus of claim 26, wherein said roller rotates during spreading in a direction counter to the direction of horizontal motion of said roller.

28. The apparatus of claim 24, wherein said doctor blade has a straight edge for spreading.

29. The apparatus of claim 24, wherein said doctor blade has a curved edge for spreading.

30. The apparatus of claim 24, wherein said distribution means comprises a doctor blade.

31. The apparatus of claim 24, wherein said distribution means comprises an elongate roller for spreading.

32. The apparatus of claim 24, wherein said roller rotates during spreading in a direction counter to the direction of horizontal motion of said roller.

33. The apparatus of claim 24, wherein said roller vibrates while compacting said powder.

34. The apparatus of claim 33, wherein said vibration is in a direction essentially orthogonal to a surface of said powder.

35. The apparatus of claim 23, wherein said distribution means comprises a doctor blade.

36. The apparatus of claim 23, wherein said distribution means comprises an elongate roller for spreading.

37. The apparatus of claim 36, wherein said roller rotates during spreading in a direction counter to the direction of horizontal motion of said roller.

38. The apparatus of claim 36, wherein said roller vibrates while compacting said powder.

39. The apparatus of claim 38, wherein said vibration is in a direction essentially orthogonal to a surface of said powder.