The traditional liquid die casting metal from liquid solidification to solid state needs first liquid shrinkage in pure liquid state, then solidification shrinkage in semi-solid stage, and finally completes solid shrinkage when it is close to solid phase. Due to the great change of density in solid and liquid state, the product shrinkage is large during solidification shrinkage, especially in some thick wall products From semi-solid solidification to solid-state solidification, it only needs to go through the solidification shrinkage stage of semi-solid stage and the solid shrinkage near the solid stage, which can effectively reduce the defects caused by volume shrinkage