The lost wax casting mold is used to obtain the structural shape of the part. It is made of other easily-formable materials in advance to form the structure of the part. Then the stainless steel casting mold is placed in the sand mold, so that a cavity of the same size as the part structure is formed in the sand mold. In the cavity, a liquid is poured again, and after the liquid is cooled and solidified, investment casting components identical to the shape of the mold can be formed.