ABSTRACT
The casting processes can be classified by the type of mold used (permanent or expendable/consumable), by the type of pattern, which also can be either permanent or expendable/consumable, and by the type of production (either continuous or discrete). Processes that have permanent molds generally require high production quantities because of the high expense of the mold. The consumable molds can be either high or low production. The patterns for consumable molds may be either permanent patterns, which can be reused, or expendable, as in the lost-wax process or the styrofoam process. Expendable patterns tend to be higher cost, but they permit production of more intricate shapes. Permanent patterns are made of wood, plastic, or metal, depending upon the "permanence" required of the pattern. A classification system of the casting processes based upon their mold and pattern or production type is presented in Table 9.1.
