Thermal Isolation for Casting Articles

• US 20130269902A1
• Filed: 03/15/2013
• Published: 10/17/2013
• Est. Priority Date: 04/12/2012
• Status: Active Grant

• Current Assignee: REL, Inc.
• Original Assignee: REL, Inc.
• Inventors: Loukus, Josh E., Loukus, Adam R.
• Granted Patent: US 9,180,511 B2
• Time in Patent Office: Days
• US Class Current: 164/97
• CPC Class Codes: B22C 9/00 Moulds or cores uniquely adapted to particular casting processes B22D; Moulding processes
• CPC Class Codes: B22D 17/00 Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
• CPC Class Codes: B22D 17/2023 Nozzles or shot sleeves
• CPC Class Codes: B22D 17/203 Injection pistons B22D17/2053 takes precedence; for plastics B29C45/53
• CPC Class Codes: B22D 17/22 Dies manufacture, see the appropriate class, e.g. B23P15/24; Die plates; Die supports; Cooling equipment for dies; Accessories for loosening and ejecting castings from dies
• CPC Class Codes: B22D 19/0081 pretreatment of the insert, e.g. for enhancing the bonding between insert and surrounding cast metal
• CPC Class Codes: B22D 19/02 for making reinforced articles B22D19/14 takes precedence
• CPC Class Codes: B22D 19/08 for building-up linings or coverings, e.g. of anti-frictional metal
• CPC Class Codes: B22D 19/14 the objects being filamentary or particulate in form making alloys containing fibres or filaments by contacting the fibres or filaments with molten metal C22C47/08
• CPC Class Codes: B22D 27/04 Influencing the temperature of the metal, e.g. by heating or cooling the mould
• CPC Class Codes: C04B 14/46 Rock wool ; Ceramic or silicate fibres C04B14/40, C04B14/42 take precedence
• CPC Class Codes: C04B 2111/00525 for metallic surfaces
• CPC Class Codes: C04B 2111/00577 applied by spraying mixtures shapable by spraying C04B2111/00155
• CPC Class Codes: C04B 30/02 containing fibrous materials
• CPC Class Codes: Y10T 428/24926 including ceramic, glass, porcelain or quartz layer

Abstract

Some embodiments provide methods and systems for casting articles. One example of a method includes providing and positioning a thermal blanket within a mold cavity and then introducing a molten material into the mold cavity and into contact with the thermal blanket. The method allows the molten material to remain in a molten state during a dwell time that extends from the introduction of the molten material at least until the mold cavity is filled. In another example, a method of using a thermal blanket includes keeping a molten material in a molten state during a dwell time extending from first introduction of the molten material until pressurization. Systems including a variety of mold types, one or more thermal blankets, and in some cases preforms and/or inserts are also provided. Also described is a novel thermal blanket and method of manufacturing the same.

Claims

1. A method for casting an article, comprising:

providing a thermal blanket, the thermal blanket comprising a layer of thermally insulating material and having a first surface and a second surface;

positioning at least a portion of the thermal blanket within a mold cavity; and

introducing a molten material into the mold cavity and into contact with the first surface of the thermal blanket until the molten material fills the mold cavity, wherein the molten material within the mold cavity remains in a molten state during a dwell time extending from the introducing of the molten material into the mold cavity at least until the molten material fills the mold cavity.

2. The method of claim 1, wherein the second surface of the thermal blanket is adjacent at least a portion of an inner surface of the mold cavity.

3. The method of claim 1, wherein the mold cavity comprises a first surface defined by at least a portion of a mold and wherein the second surface of the thermal blanket substantially covers the first surface of the mold cavity.

4. The method of claim 1, further comprising positioning a porous preform and/or a non-porous insert within the mold cavity, wherein the thermal blanket isolates the molten material from at least part of the porous preform and/or at least part of the non-porous insert during the dwell time.

5. The method of claim 1, wherein the molten material comprises at least one metal.

6. The method of claim 5, wherein the at least one metal comprises aluminum, magnesium, and/or steel.

7. The method of claim 5, wherein the molten material further comprises a particulate material.

8. The method of claim 1, wherein the thermal blanket is a first thermal blanket, and further comprising providing a second thermal blanket, the second thermal blanket comprising a layer of thermally insulating material and having a first surface and a second surface, and further comprising positioning at least a portion of the second thermal blanket within the mold cavity.

9. The method of claim 8, wherein the molten material is a first molten material, and further comprising positioning at least the portion of the second thermal blanket adjacent the first molten material and introducing a second molten material into the mold cavity and into contact with the first surface of the second thermal blanket.

10. The method of claim 9, wherein the first molten material and the second molten material are different.

11. A method for casting an article, comprising:

providing a thermal blanket, the thermal blanket comprising a layer of thermally insulating material and having a first surface and a second surface;

positioning at least a portion of the thermal blanket within a mold cavity;

introducing a molten material into the mold cavity and into contact with the first surface of the thermal blanket; and

applying pressure to the molten material until the molten material solidifies to form at least a portion of a cast article, wherein

the molten material within the mold cavity remains in a molten state during a dwell time extending from the introducing of the molten material into the mold cavity to the applying of pressure to the molten material.

12. The method of claim 11, wherein the applying pressure comprises filling the mold cavity with the molten material and continuing to introduce the molten material into the mold cavity after filling the mold cavity.

13. The method of claim 11, wherein the mold cavity is defined by at least a first mold portion and a second mold portion, and wherein the applying pressure comprises closing the first mold portion upon the second mold portion and upon the molten material within the mold cavity.

14. The method of claim 11, wherein the molten material does not penetrate the first surface of the thermal blanket prior to applying the pressure to the molten material.

15. The method of claim 11, wherein applying the pressure to the molten material causes the molten material to infiltrate the thermal blanket.

16. The method of claim 15, wherein applying the pressure to the molten material breaks apart the thermal blanket.

17. The method of claim 15, wherein applying the pressure to the molten material substantially disintegrates the thermal blanket.

18. The method of claim 11, wherein the second surface of the thermal blanket is adjacent at least a portion of an inner surface of the mold cavity.

19. The method of claim 11, wherein the mold cavity comprises a first surface defined by at least a portion of a mold and wherein the second surface of the thermal blanket substantially covers the first inner surface of the mold cavity.

20. The method of claim 11, further comprising positioning a porous preform and/or non-porous insert within the mold cavity, wherein the thermal blanket isolates the molten material from at least part of the porous preform and/or at least part of the non-porous insert during the dwell time.

21. The method of claim 11, wherein the molten material comprises at least one metal.

22. The method of claim 21, wherein the at least one metal comprises aluminum and/or magnesium.

23. The method of claim 21, wherein the molten material further comprises a particulate material.

24. The method of claim 11, wherein the thermal blanket is a first thermal blanket, and further comprising providing a second thermal blanket, the second thermal blanket comprising a layer of thermally insulating material and having a first surface and a second surface, and further comprising positioning at least a portion of the second thermal blanket within the mold cavity.

25. The method of claim 24, wherein the molten material is a first molten material, and further comprising positioning at least the portion of the second thermal blanket adjacent the first molten material, introducing a second molten material into the mold cavity and into contact with the first surface of the second thermal blanket, and wherein the applying pressure to the molten material comprises applying pressure to the first molten material and the second molten material until the first and the second molten materials solidify.

26. The method of claim 25, wherein the first molten material and the second molten material are different.

27. A system for casting an article, comprising:

a mold defining a mold cavity comprising an inner surface; and

at least one thermal blanket, the at least one thermal blanket comprising a layer of thermally insulating material, wherein the at least one thermal blanket is configured to isolate a molten material introduced into the mold cavity from the inner surface of the mold cavity such that the molten material within the mold cavity remains in a molten state at least until the molten material fills the mold cavity.

28. The system of claim 27, wherein the at least one thermal blanket is configured to isolate the molten material from the inner surface of the mold cavity until pressure is applied to the molten material.

29. The system of claim 27, wherein the at least one thermal blanket is configured to substantially disintegrate when pressure is applied to the molten material.

30. The system of claim 27, further comprising a plurality of thermal blankets.

31. The system of claim 27, wherein the at least one thermal blanket consists essentially of the layer of thermally insulating material.

32. The system of claim 27, wherein the at least one thermal blanket consists of the layer of thermally insulating material.

33. The system of claim 27, wherein the thermally insulating material comprises a ceramic fiber material.

34. The system of claim 33, wherein the ceramic fiber material comprises aluminum oxide and/or silica.

35. The system of claim 27, wherein the layer of thermally insulating material has a density of between about 6 lbs/ft³ and about 12 lbs/ft³.

36. The system of claim 35, wherein the density of the layer of thermally insulating material is about 9 lbs/ft³.

37. The system of claim 27, wherein the at least one layer of thermally insulating material has a thickness of less than about 0.0625 inches.

38. The system of claim 27, wherein the at least one layer of thermally insulating material has a thickness of between about 0.0001 inches and about 0.0625 inches.

39. The system of claim 38, wherein the thickness of the at least one layer of thermally insulating material is between about 0.03 inches and about 0.06 inches.

40. The system of claim 27, wherein the at least one layer of thermally insulating material has a thickness of about 0.03 inches.

41. The system of claim 27, further comprising a pressure injection system configured to introduce the molten material into the mold cavity under pressure.

42. The system of claim 27, wherein the mold comprises a first part and a removable second part that define the mold cavity when the removable second part is positioned adjacent the first part.

43. The system of claim 27, wherein the mold and the mold cavity are configured for gravity casting.

44. The system of claim 27, further comprising a shot sleeve configured to receive the molten material and a plunger configured to press the molten material from the shot sleeve into the mold cavity under pressure.

45. A thermal blanket for use in casting an article, comprising a layer of thermally insulating material comprising a first surface, a second opposing surface, and one or more sublayers of a ceramic fiber material, each sublayer comprising an arrangement of ceramic fibers substantially positioned in an X-Y orientation parallel to the first surface and at least partially sintered together, wherein the layer of thermally insulating material has a thickness of less than about 0.0625 inches.

46. The thermal blanket of claim 45, wherein the layer of thermally insulating material has a density of between about 6 lbs/ft³ and about 12 lbs/ft³.

47. The thermal blanket of claim 45, wherein the thermally insulating material is a binderless material.

48. A method for making a thermal blanket for use in casting an article, comprising:

providing a layer of thermally insulating material comprising a ceramic fiber material comprising a plurality of sublayers of ceramic fibers;

compressing the layer of thermally insulating material to a density of between about 6 lbs/ft³ and about 12 lbs/ft³;

heating the layer of thermally insulating material so as to at least partially sinter together the ceramic fibers within each of the plurality of sublayers; and

removing one or more of the plurality of sublayers of ceramic fibers after sintering, the one or more of the plurality of sublayers defining the thermal blanket for use in casting the article.

49. The method of claim 48, wherein the one or more of the plurality of sublayers removed have a total thickness of less than about 0.0625 inches.

50. The method of claim 48, further comprising after heating the layer of thermally insulating material to a desired temperature, holding the thermally insulating material at the desired temperature for at least one hour.