The casting process involves pouring of liquid metal in to a mold cavity and allowing it to solidify to obtain the final cast part. The flow of molten metal into the mold cavity depends on several factors like minimum section thickness of the part, presence of corners, non-uniform cross-section of the cast, and so on. The casting processes can be broadly classified into expendable mold casting and permanent mold casting processes. |
Expendable mold casting is a generic classification that includes sand, plastic, shell, plaster, and investment (lost-wax technique) molds. All these methods use temporary, non-reusable molds. After the molten metal in the mold cavity solidifies, the mold is broken to take out the solidified cast. Expendable mold casting processes are suitable for very complex shaped parts and materials with high melting point temperature. However, the rate of production is often limited by the time to make mold rather than the casting itself. Following are a few examples of expendable mold casting processes. |
