Sand casting refers to a casting method in which castings are produced in sand molds. Steel, iron and most non-ferrous alloy castings can be obtained by sand casting methods. Because the molding materials used in sand casting are cheap and easy to obtain, and the molds are easy to manufacture, they can adapt to single-piece production, batch production and mass production of castings. For a long time, it has been the basic process in casting production. Clay and an appropriate amount of water are used as the main binder for molding sand. After the sand is made, it is directly combined and poured in a wet state. Wet casting has a long history and is widely used. The strength of green sand depends on the clay slurry formed by mixing clay and water in a certain proportion. Once the molding sand is mixed, it has a certain strength. After being pounded into a sand mold, it can meet the requirements of molding and pouring. Therefore, the amount of clay and moisture in the molding sand are very important process factors.