Thermal isolation for casting articles

• US 10,179,364 B2
• Filed: 11/06/2015
• Issued: 01/15/2019
• Est. Priority Date: 04/12/2012
• Status: Active Grant

• Current Assignee: REL, Inc.
• Original Assignee: REL, Inc.
• Inventors: Loukus, Josh E., Loukus, Adam R.
• Primary Examiner(s): Kerns, Kevin P
• Assistant Examiner(s): Ha, Steven S
• Application Number:
  US14/935,068
• Publication Number:
  US 20160059305A1
• Time in Patent Office: 1,166 Days
• 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 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;

said layer of thermally insulating material further comprising at least partially sintered ceramic fibers;

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; and

wherein the at least one thermal blanket is positionable in one piece within the mold cavity prior to casting.

2. The system of claim 1 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.

3. The system of claim 1, wherein the at least one thermal blanket is configured to substantially disintegrate when pressure is applied to the molten material.

4. The system of claim 1, further comprising a plurality of thermal blankets.

5. The system of claim 1, wherein the thermal blanket consists essentially of the layer of thermally insulating material.

6. The system of claim 1, wherein the thermal blanket consists of the layer of thermally insulating material.

7. The system of claim 1, wherein the thermally insulating material comprises a ceramic fiber material.

8. The system of claim 1, wherein the at least partially sintered ceramic fiber material comprises aluminum oxide and/or silica.

9. The system of claim 1, wherein the layer of thermally insulating material has a density of between about 6 lbs/ft³ and about 12 lbs/ft³.

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

11. The system of claim 1, wherein the at least one layer of thermally insulating material has a thickness of less than about 0.0625 inches.

12. The system of claim 1, wherein the at least one layer of thermally insulating material has a thickness of between about 0.0001 inches and about 0.0625 inches.

13. The system of claim 12, wherein the thickness of the at least one layer of thermally insulating material is between about 0.03 inches and about 0.06 inches.

14. The system of claim 1, wherein the at least one layer of thermally insulating material has a thickness of about 0.03 inches.

15. The system of claim 1, further comprising a pressure injection system configured to introduce the molten material into the mold cavity under pressure.

16. The system of claim 1, 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.

17. The system of claim 1, wherein the mold and the mold cavity are configured for gravity casting.

18. The system of claim 1, 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.

19. The system of claim 1, wherein the layer of thermally insulating material comprises a compressed insulating material.

20. The system of claim 1, wherein the molten material remaining in the molten state at least until the molten material fills the mold cavity comprises the molten material remaining at a temperature above a liquidus temperature for the molten material at least until the molten material fills the mold cavity.

21. A system for casting an article, the system comprising:

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

at least one thermal blanket, the at least one thermal blanket comprising a layer of compressed thermally insulating material;

said layer of thermally insulating material further comprising at least partially sintered ceramic fibers;

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 for a dwell time of at least 30 seconds; and

wherein the at least one thermal blanket is positionable in one piece within the mold cavity prior to casting.