Sand Casting

Sand casting, also known as sand molded casting, is a metal castingprocess 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 60% of all metal castings are produced via sand casting process.

Molds made of sand are 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 the 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 called patterns, by carving directly into the sand, or by 3D printing.

Advantages

Sand is inexpensive and rich in resources. Most of the used wet clay sand can be recycled after the sand treatment. The manufacturing cycle of moulding can be completed in short terms with high efficiency in process. The mixed molding sand can be used for a long time with wild usage.

Disadvantages:

Each sand mould can only be poured once since the mould will be damaged when the casting is obtained. Therefore, the productivity of sand molded casting is relatively low.

The rigidity of sand moulds is typically lower than other types of castings. And the dimensional accuracy of the casting is also relatively lower. The castings from sand are prone to have sand leftover, inclusions, porosities or other defects.