Patent ID: 8770260

Claim:
A method for manufacturing two or more cast parts, comprising: (i) using a rapid prototyping process to print a three-dimensional tree of a sacrificial material, the tree comprising runners and/or sprues as well as two or more individual male patterns of the parts to be cast, the runners and/or sprues as well as the two or more individual male patterns being printed together as a single structure, wherein the individual male patterns are joined by the runners and/or sprues to form the tree of sacrificial material, (ii) forming a mold around the tree of sacrificial material, wherein the finished mold comprises a solid shell defining the negative pattern of the tree, and a reinforcing structure reinforcing said shell, the reinforcing structure defined by at least 50% voids, (iii) removing the sacrificial material from the mold, (iv) casting metal into the mold, (v) separating the mold from the casting, and (vi) separating the cast parts.