NINGBO RUITUO INDUSTRY & TRADE COMPNAY LIMITED.

Core and pattern manufacture for investment casting

Method and apparatus for making a ceramic core or fugitive pattern for use in investment castings wherein a fluid ceramic core or pattern material is introduced into a molding cavity defined by cooperating dies, and at least a region of one or both of the dies is heated during filling of the molding cavity with the material and then cooled to a lower ejection temperature before removal of a ceramic core or pattern from the molding cavity.

1. A method of making a molded body for use in investment casting, comprising filling a molding cavity disposed between cooperating dies with a fluid material selected to form a ceramic core or a fugitive pattern, heating at least a region of at least one of said dies to a superambient temperature during filling of said molding cavity, and cooling said local region to a lower temperature before removal of a molded body from said molding cavity.
2. The method of claim 1 wherein said region of said at least one of said dies is heated and cooled by at least one thermoelectric element disposed thereon.
3. The method of claim 2 including sensing temperature of said region and controlling said at least one thermoelectric element in response to sensed temperature.
4. The method of claim 2 wherein said region comprises a trailing edge-shaped region of an airfoil, said trailing edge-shaped region being heated prior to and during filling of said molding cavity and cooled before removal of said molded body from said molding cavity.
5. The method of claim 4 wherein said trailing edge-shaped region includes relatively narrow channels that are heated by said at least one thermoelectric element to permit filling thereof with said fluid material.
6. The method of claim 1 wherein said region of said at least one of said dies is heated and cooled by at least one fluid passage disposed therein.
7. The method of claim 2 including removing heat from said at least one thermoelectric element using a heat exchange fluid.
8. The method of claim 7 wherein said heat exchange fluid is selected from the group consisting of a liquid and gas.
9. The method of claim 1 wherein said fluid material comprises a ceramic core material comprising ceramic flour and a fluid binder.
10. The method of claim 1 wherein said fluid material comprises a pattern material selected from the group consisting of a wax and a polymer.
11. Apparatus for molding an airfoil-shaped body for use in casting a metallic airfoil, comprising first and second dies defining a molding cavity having an airfoil-shaped cavity, and at least one thermoelectric element disposed on at least one of said dies to heat at least a hard-to-fill region of said cavity to a superambient temperature during filling of said molding cavity with a fluid material, and to cool said region to a lower temperature before an airfoil-shaped body is removed from said molding cavity.
12. The apparatus of claim 11 including a temperature sensor proximate said region and an electrical power controller connected to said at least one thermoelectric element to control electrical power thereto in response to sensed temperature.
13. The apparatus of claim 11 including a heat exchanger in thermal contact with said thermoelectric element.
14. The apparatus of claim 13 including an inlet conduit conducting a heat exchange fluid to said heat exchanger to remove heat therefrom and an outlet conduit for exhausting said heat exchange fluid.
15. The apparatus of claim 11 including a thermally conductive material disposed between said at least one thermoelectric element and said at least one of said dies for conducting heat from said at least one thermoelectric element.
16. The apparatus of claim 11 wherein said molding cavity has a configuration of a ceramic core.
17. The apparatus of claim 11 wherein said molding cavity has a configuration corresponding to a pattern that replicates said airfoil-shaped body.
18. Apparatus for molding an airfoil-shaped body for use in casting a metallic airfoil, comprising first and second dies defining a molding cavity having an airfoil-shaped cavity, and at least one fluid passage on at least one of said dies to provide a fluid to heat at least a hard-to-fill region of said cavity to a superambient temperature during filling of said molding cavity with a fluid material, and to cool said region to a lower temperature before an airfoil-shaped body is removed from said molding cavity.
19. The apparatus of claim 18 wherein said molding cavity has a configuration of a ceramic core.
20. The apparatus of claim 18 wherein said molding cavity has a configuration corresponding to a pattern that replicates said airfoil-shaped body.