PURPOSE: To shorten the time required for melting a core and removing the same by heating synthetic resin and the core of low melting point metal released out of a molding tool to the temperature higher than the melting point of low melting point metal and lower than the melting point of synthetic resin to melt the core removed from the synthetic resin and using the hollow core for the purpose in said heating process.
CONSTITUTION: Synthetic resin with melting point higher than that of low melting point metal is injected into a molding tool in the state that a hollow core 1 made of low melting point metal is set therein and solidified, and then the synthetic resin and the core 1 released out of the molding tool are heated to the temperature higher than the melting point of low melting point metal and lower than the melting point of synthetic resin to melt the low melting point metal, and the core 1 is released out of the synthetic resin. In the case of manufacturing the hollow insert die 1, molten low melting point metal 3 (molten material) is injected into a casting mold 2, and after a short time the uncured molten material is discharged out of the casting mold 2. As the molten material injected into the casting mold 2 is cooled and solidified starting from the outside section being in contact with the inner face of the casting mold 2 of low temperature, a hollow insert die 1 is manufactured.
FUNATSU TAKASHI
KAMIMURA FUJIO
