ABSTRACT

The lost foam casting process is also known as evaporative pattern casting (EPC), full mold casting, polycast, or replicast. In this process (Fig. I), liquid metal is poured directly onto a refractory-coated foamed polymer pattern, which is buried in loose sand. The polymer pattern undergoes thermal degradation and is progressively liquefied, vaporized, and replaced by the molten metal, which solidifies and produces the casting. The most commonly used foam materials in EPC process are expanded polystyrene (EPS) and polymethyl methacrylate (PMMA). Currently, the EPC process is utilized to manufacture a wide variety of ferrous and nonferrous components catering primarily to the automotive industry. There are about 30 foundries in North America that are committed to the lost foam casting process [1-4].