Patent ID: 7905273
Filing Date: 2011-03-15
Classification: B22C

Abstract:
1. A method of forming a cast metal article, said method comprising the steps of providing a ceramic base core having a first coefficient of thermal expansion, positioning a core element having a second coefficient of thermal expansion in an opening formed in the ceramic base core, filling the opening in the ceramic base core with a filler material having a third coefficient of thermal expansion, said third coefficient of thermal expansion being greater than said first coefficient of thermal expansion and less than said second coefficient of thermal expansion, firing the ceramic base core without cracking the base core and without cracking the filler material, at least partially covering the ceramic base core and the core element with wax to form a pattern assembly having a configuration corresponding to a desired configuration of at least a portion of the cast metal article, at least partially enclosing the pattern assembly with a wet layer of ceramic mold material, firing the wet layer of ceramic mold material to form a mold, removing the wax from the mold to leave within the mold a space having a configuration corresponding to the desired configuration of the cast metal article, filling the space in the mold with molten metal, and solidifying the molten metal to form the cast metal article.