For the production of complicated plastic parts in a cycle, a mold is needed.. The basic tasks of a mold are accommodation and distribution of the resin, shaping and cooling the melt and ejection of the molding. To achieve these goal a mold has several important parts and we classified types of molds. The 6 different major functions of a mold are explained and several types of molds are shown in her. I hope these explanation will help to understand injection molds for a design engineer.