Quasi self-destructive core for investment casting

Abstract

A composite core for forming a passage in an investment casting mold is provided including a generally hollow structural element. The structural element is configured to deform when a force is applied to an end thereof. A rigid shell element is formed about the structural element. The shell element extends beyond both an interior surface and an exterior surface of the structural element. The shell element is configured to shatter when the structural element deforms.

Description

This invention was made with Government support under N00019-06-C-0081 awarded by the Department of the Navy. The Government has certain rights in this invention.BACKGROUND OF THE INVENTION[0001]Exemplary embodiments of the invention generally relate to investment casting, and more particularly, to a core for forming a passage in an investment casting mold.[0002]Investment casting is a commonly used technique for forming metallic components having complex shapes and geometries, especially hollow components such as those used in aerospace applications for example. The production of an investment cast part generally involves producing a ceramic casting mold having an outer ceramic shell with an inside surface corresponding to the shape of the part, and one or more ceramic cores positioned within the outer ceramic shell, corresponding to interior passages to he formed within the part, Molten alloy is introduced into the ceramic casting mold and is then allowed to cool and to harden. Th...

AI Technical Summary

Benefits of technology

This patent describes a composite core for use in investment casting molds. The core is made up of a hollow structural element that can deform when a force is applied to one end, and a rigid shell element that extends beyond the interior and exterior surfaces of the structural element. This shell element is designed to shatter when the structural element deforms. The composite core can be made by arranging a core element inside the hollow structural element and layering slurry around it, then heating it to melt the core element. The composite core can then be used to form a passage in a cast component by arranging it in the mold and allowing material to flow into it. The core prevents the passage from collapsing or expanding during the casting process, resulting in a more precise and reliable component.

Problems solved by technology

However, investment casting is limited by the design of passages within the mold.

Unlike a sand core used in a sand casting process, the ceramic cores used in CSIC are difficult to remove or destroy without affecting the molded part.

As a result, the process of designing passages severely restricts the use of CSIC for applications requiring complex cored passages.

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