It has excellent thermoformability, high deformability and tensile strength. The successful rate of plastic moulding has reached 93-95% according to the size of castings, and the use efficiency is equal to the quality level of similar products abroad. Vacuum moulding technology is a new physical method created by the foundry industry in the late 1970s. It has good casting quality, high dimensional accuracy, smooth surface, no sand holes, no air holes and other defects.