Compliant cantilevered micromold and use thereof in replication of cantilevered microparts

• US 20030057096A1
• Filed: 08/15/2002
• Published: 03/27/2003
• Est. Priority Date: 01/17/2001
• Status: Active Grant

• Current Assignee: National Technology & Engineering Solutions Of Sandia LLC (Honeywell International Inc.)
• Original Assignee: Sandia National Laboratories (Government of the United States of America)
• Inventors: Keifer, Patrick N., Domeier, Linda A., Gonzales, Marcela G., Morales, Alfredo Martin, Garino, Terry Joseph
• Granted Patent: US 7,090,189 B2
• Time in Patent Office: Days
• US Class Current: 205/67
• CPC Class Codes: B29C 2045/0094 injection moulding of small-sized articles, e.g. microarticles, ultra thin articles
• CPC Class Codes: B29C 33/0016 Lost moulds, e.g. staying on the moulded object flexible bags without particular shape filled with expandable material B29C44/182; single use mandrels for winding and forming B29C53/822
• CPC Class Codes: B29C 33/3857 by making impressions of one or more parts of models, e.g. shaped articles and including possible subsequent assembly of the parts
• CPC Class Codes: B29C 33/52 soluble or fusible in particular used in injection moulding B29C45/4457
• CPC Class Codes: C25D 1/10 Moulds; Masks; Masterforms

Abstract

A compliant cantilevered three-dimensional micromold is provided. The compliant cantilevered micromold is suitable for use in the replication of cantilevered microparts and greatly simplifies the replication of such cantilevered parts. The compliant cantilevered micromold may be used to fabricate microparts using casting or electroforming techniques. When the compliant micromold is used to fabricate electroformed cantilevered parts, the micromold will also comprise an electrically conducting base formed by a porous metal substrate that is embedded within the compliant cantilevered micromold. Methods for fabricating the compliant cantilevered micromold as well as methods of replicating cantilevered microparts using the compliant cantilevered micromold are also provided.

Claims

1. A compliant cantilevered micromold, comprising a compliant polymeric material having cantilevered microscale features formed therein.

2. The compliant cantilevered micromold of claim 1, wherein said compliant polymeric material contains at least one filler.

3. The compliant cantilevered micromold of claim 1, wherein the compliant polymeric material comprises a polymer selected from the group consisting of polysiloxanes, polyalkylenes, and polyurethanes, and derivatives and copolymers thereof.

4. The compliant cantilevered micromold of claim 3, wherein the compliant polymeric material is a polysiloxane.

5. The compliant cantilevered micromold of claim 4, wherein the polymer is poly(dimethylsiloxane).

6. The compliant cantilevered micromold of claim 1, further comprising a porous metal material embedded within the compliant polymeric material and having an upper surface, wherein the cantilevered microscale features project from said upper surface of the porous metal material.

7. The compliant cantilevered micromold of claim 6, wherein the porous metal material substrate is comprised of an electroplatable material.

8. The compliant cantilevered micromold of claim 7, wherein more than one porous metal material is embedded in said polymeric substrate.

9. The compliant cantilevered micromold of claim 6, wherein the porous metal material is selected from the group consisting of a metal mesh, a sintered metal mesh, a perforated metal screen, an etched metal screen, a metal foam, a metal felt, and a metal mat.

10. The compliant cantilevered micromold of claim 6, wherein said porous metal material is comprised of a metallic material selected from the group consisting of Cu, Ni, Ti, Al, Ag, Au, Pt, stainless steel, and combinations thereof.

11. The compliant cantilevered micromold of claim 6, wherein said porous metal material comprises a porous metal structure covered by a metallic coating.

12. The compliant cantilevered micromold of claim 11, wherein the porous metal material and the metal coating are comprised of different metals.

13. The compliant cantilevered micromold of claim 11, wherein the metallic coating is comprised of copper.

27. A method for replicating a cantilevered micropart comprising:

a) providing the compliant cantilevered micromold of claim 1;

b) filling the cantilevered micromold with a castable or curable molding composition;

c) hardening or curing the molding composition to form the cantilevered micropart; and

d) removing the compliant cantilevered micromold thereby releasing the cantilevered micropart.

28. The method claim 27, wherein the molding composition further comprises at least one of an optional curing agent, a cure accelerator, a cure inhibitor, and an internal mold release agent.

29. The method of claim 27, wherein the molding composition comprises materials selected from the group consisting of vinyl monomers, acrylic monomers, silicon-containing monomers, and polymers, copolymers and blends thereof.

30. The method of claim 29, wherein the molding composition comprises materials selected from the group consisting of diallyl phthalates, maleimides, acetylene-terminated monomers, styrene, divinylbenzene, and modified styrene monomers.

31. The method of claim 29, wherein the molding composition comprises a silicon-containing monomer.

32. The method of claim 31, wherein the molding composition is selected from the group consisting of dimethyl siloxane, diphenyl siloxane, methylvinyl siloxane, and methylphenyl siloxane monomers.

33. The method of claim 27, wherein the molding composition comprises monomers selected from the group consisting of epoxy resins and hardeners, and polyurethane precursors.

34. The method of claim 27, wherein the molding composition is a thermally curable polymer and step (c) is conducted by heating the molding composition to a temperature sufficient to cure the thermally curable polymer.

35. The method of claim 27, wherein the molding composition comprises a chemically curable polymer, and the molding material additionally includes a curing agent.

36. The method of claim 35, wherein the molding composition comprises an epoxy resin and hardener.

37. The method of claim 27, wherein the molding composition comprises a photolytically curable polymer, and step (c) is conducted by irradiating the molding material.

38. The method of claim 37, wherein step (c) is conducted by irradiating the molding material with an electron beam.

39. The method of claim 27, wherein the molding composition further includes a filler selected from the group consisting of inorganic fillers, metal powders, and mixtures thereof.

40. The method of claim 39, further comprising, after step (c), pyrolyzing and sintering the cantilevered micropart to provide a densified cantilevered micropart by heating to a temperature effective to remove organic material contained therein and to produce densification of the inorganic component.

41. A method for fabricating a cantilevered micropart comprising:

a) providing the compliant cantilevered micromold of claim 7;

b) electroplating the cantilevered micromold thereby filling the compliant cantilevered micromold with electroformed metal thereby forming an electroformed cantilevered micropart therein; and

c) removing the compliant cantilevered micromold to release the electroformed cantilevered micropart.

42. The method of claim 41, further comprising lapping a portion of the electroformed metal.

43. The method of claim 41, further comprising lapping the porous metal material.

44. The method of claim 41, wherein the porous metal material and the electroformed cantilevered micropart are comprised of different metals.

45. The method of claim 44, further comprising dissolving the porous metal material without dissolving the electroformed cantilevered micropart.

46. The method of claim 41, wherein the porous metal material is comprised of a porous metal structure covered by a metal coating.

47. The method of claim 46, wherein the porous metal material and the metal coating are comprised of different metals.

48. The method of claim 47, further comprising dissolving the metal coating, thereby releasing the electroformed cantilevered micropart from the porous metal material.

14. A method for fabricating a compliant cantilevered micromold comprising the steps of:

a) infusing a compliant polymeric material into a patterned surface of a tooled master part comprising cantilevered features so as to conform the compliant polymeric material to the cantilevered features, resulting in microscale cantilevered features formed from the compliant polymeric material;

b) hardening or polymerizing the infused compliant polymeric material; and

c) separating the tooled master part from the hardened or polymerized infused compliant polymeric material to provide a compliant cantilevered micromold.

15. The method of claim 14, wherein said compliant polymeric material is capable of being cast or injection-molded.

16. The method of claim 14, wherein said compliant polymeric material contains at least one filler.

17. The method of claim 14, wherein the compliant polymeric material comprises a polymer selected from the group consisting of polysiloxanes, polyalkylenes, and polyurethanes, and derivatives and copolymers thereof.

18. The method of claim 17, wherein the compliant polymeric material is a polysiloxane.

19. The method of claim 18, wherein the polymer comprises poly(dimethylsiloxane).

20. A method for fabricating a compliant cantilevered micromold having an electroplatable backing comprised of a porous metal material, the method comprising the steps of:

a) infusing a compliant polymeric material through a porous metal material into a tooled master part having cantilevered features therein so as to conform the compliant polymeric material to the cantilevered features;

b) hardening or polymerizing the infused compliant polymeric material; and

b) separating the tooled master part from the porous metal substrate and the hardened or polymerized compliant polymeric material to provide a compliant cantilevered micromold having an electrically conducting backing.

21. The method of claim 20, wherein said compliant polymeric material is capable of being cast or injection-molded.

22. The method of claim 20, wherein said compliant polymeric material contains at least one filler.

23. The method of claim 21, wherein the compliant polymeric material is selected from the group consisting of polysiloxanes, polyalkylenes, and polyurethanes, and derivatives and copolymers thereof.

24. The method of claim 23, wherein the compliant polymeric material is a polysiloxane.

25. The method of claim 24, wherein said compliant polymeric material comprises poly(dimethylsiloxane).

26. The method of claim 20, wherein more than one porous metal material is infused with the compliant polymeric material.