Profile: Dongguan Sincere Tech Co. Ltd. is a manufacturer of plastic molds. We specialize in aluminium die casting, magnesium die casting, zinc die casting and other metals. Plastic injection mold is metal steel that has been made the hollow base apart sharp and later filled with a liquid or any other material. Some of the material that can be poured into the hollow space of the steel include plastic, metal, glass and even ceramic materials. The liquid is allowed to solidify and the block is broken to retrieve the mold that has acquired the shape of the block. Plastic mold is a custom mold that is used for making custom injection molding parts.