The gravity casting is one type of permanent mold casting. The gravity casting main advantages are the reusable mold, good surface finish, good dimensional accuracy, and high production rates.
Sand casting also called sand mold casting, it's used to produce a wide variety of metal components with complex geometries. These metal parts can vary greatly in size and weight, ranging from a couple ounces to several tons. The small sand cast parts include as gears, pulleys, crankshafts etc.