METHOD OF CASTING A COMPONENT HAVING INTERIOR PASSAGEWAYS

• US 20110293434A1
• Filed: 04/15/2011
• Published: 12/01/2011
• Est. Priority Date: 06/01/2010
• Status: Active Grant

• Current Assignee: Mikro Systems, Inc., Siemens Energy Incorporated (Siemens AG)
• Original Assignee: Mikro Systems, Inc., Siemens Energy Incorporated (Siemens AG)
• Inventors: Lee, Ching-Pang, Burns, Andrew J., Merrill, Gary B.
• Granted Patent: US 8,936,068 B2
• Time in Patent Office: Days
• US Class Current: 416/229.R
• CPC Class Codes: B22C 7/02 Lost patterns
• CPC Class Codes: B22C 7/026 by assembling preformed parts joining of plastics, in general B29C65/00
• CPC Class Codes: B22C 9/04 Use of lost patterns
• CPC Class Codes: B22C 9/043 Removing the consumable pattern
• CPC Class Codes: B22C 9/22 Moulds for peculiarly-shaped castings
• 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 29/00 Removing castings from moulds, not restricted to casting processes covered by a single main group; Removing cores; Handling ingots B22D13/10, B22D11/124, B22D17/00 take precedence
• CPC Class Codes: Y10T 428/12361 having aperture or cut

Abstract

A method of casting a component (42) having convoluted interior passageways (44). A desired three dimensional structure corresponding to a later-formed metal alloy component is formed by stacking a plurality of sheets (18, 20) of a fugitive material.

The sheets contain void areas (22) corresponding to a desired interior passageway in the metal alloy component. A ceramic slurry material is cast into the three dimensional structure to form either a ceramic core (34) or a complete ceramic casting vessel (38). If just a ceramic core is formed, a wax pattern is formed around the ceramic core and an exterior ceramic shell (38) is formed around the wax pattern by a dipping process prior to the removal of the fugitive material and wax. An alloy component having the desired interior passageway is cast into the casting vessel after the fugitive material is removed.

Claims

1. A method of casting a component, the method comprising:

forming a plurality of sheets of fugitive material, each sheet corresponding to a respective layer of a desired three dimensional structure, at least some of the sheets each containing a respective void area in a location corresponding to a location of a passageway within the desired three dimensional structure;

stacking the sheets to form the three dimensional structure, void areas in adjoining sheets being aligned to define the passageway within the three dimensional structure;

injecting ceramic material slurry into the three dimensional structure and allowing the ceramic material to harden, the passageway thus being filled with the ceramic material in a shape corresponding to the passageway;

removing the fugitive material from the hardened ceramic material to reveal a cast ceramic component;

injecting molten alloy material into the cast ceramic component and allowing the alloy material to harden, the shape of the passageway thereby being reproduced in the alloy material; and

removing the cast ceramic component from the hardened alloy material to reveal a cast alloy component having an interior passageway.

2. The method of claim 1, further comprising dipping the three dimensional structure in a ceramic dipping slurry prior to removing the fugitive material to form an external shell structure around the three dimensional structure, the external shell structure and the cast ceramic component together forming a casting vessel for receiving the molten alloy material after removal of the fugitive material.

3. The method of claim 1, further comprising:

forming a first portion of the plurality of sheets of fugitive material to have a first thickness for a first region of the three dimensional structure; and

forming a second portion of the plurality of sheets of fugitive material to have a second thickness different than the first thickness for a second region of the three dimensional structure.

4. The method of claim 1, further comprising casting the sheets of fugitive material in at least two different master molds.

5. The method of claim 1, further comprising forming the sheets of fugitive material by cutting respective voids into respective integral sheets of the fugitive material.

6. A method of manufacturing comprising:

forming a plurality of sheets of fugitive material containing void areas within appropriate ones of the sheets corresponding to a layered hollow component design;

stacking the plurality of sheets to form a fugitive three dimensional structure corresponding to the hollow component design;

casting a ceramic material into the fugitive three dimensional structure; and

removing the fugitive three dimensional structure from the cast ceramic material to reveal a hollow ceramic component.

7. The method of claim 6, further comprising:

casting a metal alloy into the hollow ceramic component; and

removing the ceramic component from the cast metal alloy to reveal a hollow metal alloy component.

8. The method of claim 7, further comprising:

forming a ceramic shell around the cast ceramic material prior to the step of removing the fugitive three dimensional structure;

then

removing the fugitive three dimensional structure from the cast ceramic material and ceramic shell to reveal a ceramic casting vessel.

9. The method of claim 7, further comprising:

selecting the hollow component design to include a core structure and a surrounding shell structure which define a casting vessel such that the step of removing the fugitive three dimensional structure reveals a ceramic casting vessel; and

casting the metal alloy into the ceramic casting vessel.

10. A cast metal component formed by the process of claim 6 and comprising a plurality of interconnected interior passageways defining a plurality of three dimensional convoluted pathways which weave left and right as well as up and down around structures within the component as it moves toward an exit from the component.

11. The cast metal component of claim 10 formed to define a trailing edge portion of a gas turbine airfoil.