Evaporative pattern, method of forming an evaporative pattern, and method of forming a metal mold by using an evaporative pattern

Abstract

A lightweight metal mold having a necessary rigidity is realized. Firstly, an original pattern of an evaporative pattern is formed by machining an evaporative material block. The original pattern includes a three-dimensional mesh structure including a plurality of bar-shaped parts and connecting points that connect ends of the bar-shaped parts and are distributed in a three-dimensional space, and a plurality of block parts having fixed relative positional relationship by being fixed to the three-dimensional mesh structure. Then, at least a portion of at least one or more of the bar-shaped parts composing the original pattern is removed, and replaced with a tube member. Then, a full-mold casting is performed by using the evaporative pattern having the replaced tube member. Positional relationship of the block parts in which surfaces, etc. necessary for the metal mold are formed is fixed by the three-dimensional mesh structure, and the necessary rigidity is secured. The metal mold is made lighter by using the three-dimensional mesh structure. Due to the replacement with the tube member, an amount of gas generated upon the full-mold casting is suppressed, and a decrease in casting quality is prevented.