PRODUCTION OF CASTING MOLD

PURPOSE:To obtain a casting mold which is free from the disadvantages by foamed polystyrene in a full mold method by manufacturing the casting mold by using a foamed molding of a high-polymer material then shrinking and solidifying the foamed molding by hot air and removing the molding from the mold inside. CONSTITUTION:Molding sand is molded by using the pattern of, for example, the foamed polystyrene molding and thereafter the hot air kept at 100-200 deg.C is fed into the casting mold. The above-described pattern is shrunk and solidified and the residues of the shrunk solid produced therein are mechanically or manually removed from the mold inside. A molten metal is cast into the cavity in the mold formed in such a manner, by which the product casting is manufactured. Problems such as the generation of black smoke and fire column by the gas generated from the PE in the full mold method and the generation of blow back of the molten metal by the back flow of the generated gas in a runner are thus eliminated. There is also an advantage in that the low expansion type polystyrene can be used.