The screwy sheath of double screw roller grinded-paste machine was produced by sand casting

centrifugal casting with permanent mold and resin sand mould coupled with centrifugal casting

respectively

and three casting technologies were analyzed.The results indicate that the screwy sheath produced by sand casting has coarse grain and rougher surface with misrun flaw and shrinkage porosity on the boot of the screw

while that produced by centrifugal casting with permanent mold has high surface quality with fine grain

however

there exists misrun at the thinner location of two ends of the screwy sheath due to high cooling rate

and that produced by resin sand-centrifugal casting has excellent surface quality without defect in the microstructure with fine grain

so it is the desirable technology.