We investigated injection molding characteristics by carrying out comparative tests using an aluminum alloy mold coated using iron plating and a steel mold. In this study, a rapid heating and cooling mold temperature system was applied to the method of controlling mold temperature aiming at weldless molding. The weldless molding was made possible using an aluminum alloy mold coated by iron plating with a rapid heating and cooling mold temperature system. However, it is necessary to increase the injection start temperature by a higher value when using the aluminum alloy mold than when using the steel mold. The temperature in the aluminum alloy mold during molding was almost uniform. About 40% was what reduced in the aluminum alloy mold as a result of comparing the cycle times under weldless molding conditions. The transcript of the mold surface pattern to the product with the aluminum alloy mold was worse than that with the steel mold. However, the value was small. It was clarified that injection molding that uses an aluminum alloy mold and a rapid heating and cooling mold temperature system is effective for weldless molding.
