Investment casting mold design and method for investment casting using the same

• US 7,231,955 B1
• Filed: 01/30/2006
• Issued: 06/19/2007
• Est. Priority Date: 01/30/2006
• Status: Active Grant

• Current Assignee: Rtx Corporation
• Original Assignee: United Technologies Corporation (Rtx Corporation)
• Inventors: Bullied, Steven J., Reilly, P. Brennan
• Primary Examiner(s): Lin; Kuang Y.
• Application Number:
  US11/343,370
• Time in Patent Office: 505 Days
• Field of Search: 164 34- 36, 164/122.1, 164/122.2, 164133-136, 164516-519, 164/361
• US Class Current: 164/35
• CPC Class Codes: B22C 9/043 Removing the consumable pattern
• CPC Class Codes: B22C 9/082 Sprues, pouring cups

Abstract

A method for investment casting includes the steps of positioning a base plate relative to a die; molding a first material between the die and at least a first surface portion of the base plate; securing one or more patterns to the base plate, the one or more patterns comprising a second material; applying one or more coating layers over at least portions of the one or more patterns and at least a portion of the first material; substantially removing the first material through an interior receptacle of a manifold body and the second material through an exterior receptacle of the manifold body to leave one or more shells formed by the coating layers; removing said base plate; introducing molten metal to the one or more shells through the interior receptacle of the manifold body; permitting the molten metal to solidify; and destructively removing one or more investment casting molds.

Claims

1. A method for investment casting, comprising:

positioning a base plate relative to a die;

molding a first material between said die and at least a first surface portion of said base plate;

securing one or more patterns to said base plate, said one or more patterns comprising a second material;

applying one or more coating layers over at least portions of said one or more patterns and at least a portion of said first material;

substantially removing said first material through an interior receptacle of a manifold body and said second material through an exterior receptacle of said manifold body to leave one or more shells formed by said coating layers;

removing said base plate;

introducing molten metal to said one or more shells through said interior receptacle of said manifold body;

permitting said molten metal to solidify; and

destructively removing one or more investment casting molds.

2. The method of claim 1, wherein substantially removing comprises:

substantially removing said first material through a first feeder conduit and a first aperture in communication with said interior receptacle; and

substantially removing said second material through a vent and a substantially circular channel in communication with said exterior receptacle.

3. The method of claim 2, wherein said first material and said second material comprise one or more wax materials.

4. The method of claim 1, wherein introducing comprises introducing said molten metal through said interior receptacle in communication with a first feeder conduit leading to said pattern and exiting through a vent leading from said pattern to said exterior receptacle.

5. The method of claim 1, wherein said manifold body comprises:

a dual wall pour chamber comprising;

said interior receptacle comprising a first substantially conical shaped wall having an interior surface and an exterior surface,

said exterior receptacle comprising a second substantially conical shaped wall circumferentially disposed about said interior receptacle and having an interior surface and an exterior surface,

wherein said interior surface of said interior receptacle defines in part an aperture, and said exterior surface of said interior receptacle and said interior surface of said exterior receptacle define in part said substantially circular channel.

6. The method of claim 1 used to fabricate a gas turbine engine component.

7. A mold assembly, comprising:

a plurality of mold sections; and

a manifold body having a dual wall pour chamber comprising;

said interior receptacle comprising a first substantially conical shaped wall having an interior surface and an exterior surface,

said exterior receptacle comprising a second substantially conical shaped wall circumferentially disposed about said interior receptacle and having an interior surface and an exterior surface,

wherein said interior surface of said interior receptacle defines in part an aperture, and said exterior surface of said interior receptacle and said interior surface of said exterior receptacle define in part said substantially circular channel;

a plurality of feeder conduits, each extending from said dual wall pour chamber toward an associated one or more of said plurality of mold sections; and

a plurality of vents, each extending from said plurality of mold sections toward said dual wall pour chamber.

8. The mold assembly of claim 7, wherein plurality of mold sections comprise three or more mold sections, each mold section associated with a first feeder conduit and a second feeder conduit.

9. The mold assembly of claim 7, wherein each mold section comprises a molding cavity and a gate, said gate extending from a lower end of said molding cavity to an upper end coupled to said feeding conduit.