Sand casting, also known as sand molded casting, is a metal casting process
characterized by using sand as the mold material. The term "sand casting" can
also refer to an object produced via the sand casting process. Sand castings are
produced in specialized factories called foundries. Over 70% of all metal
castings are produced via a sand casting process.
Sand casting is relatively cheap and sufficiently refractory even for steel
foundry use. In addition to the sand, a suitable bonding agent (usually clay) is
mixed or occurs with the sand. The mixture is moistened, typically with water,
but sometimes with other substances, to develop strength and plasticity of the
clay and to make the aggregate suitable for molding. The sand is typically
contained in a system of frames or mold boxes known as a flask. The mold
cavities and gate system are created by compacting the sand around models, or
patterns, or carved directly into the sand.
There are six steps in this process:
Place a pattern in sand to create a mold.
Incorporate the pattern and sand in a gating system.
Remove the pattern.
Fill the mold cavity with molten metal.
Allow the metal to cool.
Break away the sand mold and remove the casting.