Abstract
Laser beam lithography is widely applied to trial production. Resin patterns are inferior to those of metals in heat resistant and mechanical properties. Therefore, if resin patterns can be quickly copied to metal castings, application of the process is expected to remarkably widen. After the resin pattern was set in a plaster mold and heated up to the temperature the resin completely burnt out, molten metal was cast in the mold. As a result, in case of thick patterns, cracks generated in the plaster mold. On the other hand, thin patterns could be copied to the metal castings. Cracks ware generated in the mold, sirice the coefficient of thermal expansion was higher than that of plaster, and gas pressure was increased by burning. The effects of the heating rate on mold cracks were also investigated. At low heating rates of the mold, gas pressure decreased preventing the mold from cracking, and resin patterns could be copied to metal castings. Developemnt of new photopolymers for burning patterns in the mold is required for further development of the process.
