| 摘要 |
PURPOSE:To release a core in a short time by heating the core from inside by means of application to an electric heater built-in the core when synthetic resin and the low melting point metal core released out of a molding tool are heated. CONSTITUTION:Synthetic resin having the melting point higher than that of low melting point metal is injected into a molding tool in the state that a 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 is 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. An electric heater 2 is set in the state of being insulated from the metal core 1 by covering said heater 2 with an insulated heat-resistant skin or applying some other means, and both ends of the electric heater 2 are protruded out of the end face of the core 1. The core l is heated from inside by appling power to the electric heater 2 when the synthetic resin and the core 1 released out of the molding tool are heated. |
