Sand casting, also known as sand molded casting, is a metal casting process characterized by using sand as the mold material. It is relatively cheap and sufficiently refractory even for steel foundry use. The term "sand casting" can also refer to a casting produced via the sand casting process. Sand castings are produced in specialized factories called foundries. In sand molded casting, the molten metal is poured into the cavity, which has a pattern made of wood or metal. The patterns is a exact replica of the shape that the metal is to casted in. Molten metal in introduced into the cavity in the shape of the casting to be made. When the cast solidifies the mold is broken to remove the castings. of the finished workpieces, etc. Machines are also used for handling the castings, re preparation of the sand and for mixing the components for making molds.
Applications of Sand casting (Sand Molded Casting):
Sand casting is used to produce a wide variety of metal components with complex geometries. These parts can vary greatly in size and weight, ranging from a couple ounces to several tons. Some smaller sand cast parts include components as gears, pulleys, crankshafts, connecting rods, and propellers. Larger applications include housings for large equipment and heavy machine bases. Sand molded casting is also common in producing automobile components, such as engine blocks, engine manifolds, cylinder heads, machine bases, gears, pulleys, and transmission cases.
Process of Sand casting (Sand Molded Casting):
A single piece or solid pattern is used for simple designs. Patterns that are more complex are made in two parts, and are called split patterns. This can also be designed in the CAD level, and printed by Objet systems. The upper part of a split pattern is called a cope, while the bottom section is called a drag. Where the cope and drag separate is known as the parting line. Both solid and split patterns can have cores inserted to complete the final part shape. When making a pattern, it is necessary to taper the edges so the pattern can be removed without breaking the mold.
Advantages of Sand casting (Sand Molded Casting):
1. Can produce very large parts
2. Can form complex shapes
3. Many material options
4. Low tooling and equipment cost
5. Scrap can be recycled
6. Short lead time possible