We use the investment casting process (also known as lost wax precision casting). Lost wax casting uses wax to make a wax pattern of the parts to be cast, and then coats the wax pattern with mud, which is the mud mold. After the clay mold is dry, place it in hot water to melt the wax mold inside. The clay mold that has melted the wax mold is taken out and then baked into a pottery mold. Once baked, the pouring port is usually left when making the mud mold, and then the molten metal is poured into the pouring port. After cooling, the required parts are made.