PURPOSE: To prevent the generation of misrun and to form good chill layers, by charging molten cast iron into the cavity disposed with chillers in required positions, and sucking the air in the cavity through the wall surface of a mold.
CONSTITUTION: A shell mold 3 having a cavity 2 conforming to a cam shaft is held with backup materials 4, and is contained in a vessel 5, whereby a mold 1 is constituted. Chillers 6 are embedded in the wall surfaces facing the cam noses in the many projecting parts corresponding to the cams in the cavity 2. The bottom surface of the vessel 5 has many vent holes 7, and the vessel 5 is placed on a suction box 8 in such a way that the opened part on the top surface of the box 8 is closed with said bottom surface. While the air in the box 8 is sucked with a pump, molten cast iron is charged into the cavity through a sprue 10. Then negative pressure is developed in the cavity 2, and the molten metal flows over the entire part of the cavity 2, whereby the generation of misrun is effectively prevented.
SUGA SHIGERU
SHINADA KIICHI
KOMURO TOSHIAKI
MOTOI KAZUSHIROU
