Sand casting is a metal forming process. First, a three-dimensional sand mold is formed, and then the molten metal is poured into the cavity of the sand mold for solidification. After the metal parts are cooled and formed, remove the sand shell. Some sand castings need to be processed after casting. Sand casting can produce all kinds of metal materials, including cast iron, special alloy steel, titanium alloy and so on. Sand casting is an economical and efficient technology, which can flexibly meet the requirements of size and structure design. Sand castings usually need secondary processing to improve the accuracy of products.