One of the most commonly used is investment casting, also known as lost wax casting: selecting suitable investment materials (such as paraffin) to manufacture investment molds; Repeatedly apply refractory coating and spraying process on the mold, harden the mold shell and dry it; Dissolve the internal mold to obtain the mold cavity; Baking the shell to obtain sufficient strength and burning off residual investment materials,; Metal materials required for pouring; Solidification cooling, dehulling and sand cleaning to obtain high-precision finished products. According to the product's needs or through heat treatment, cold processing, and surface treatment.