| 摘要 |
PURPOSE:To avert the breakage of projecting parts and to efficiently vent gas by loosely inserting the projecting parts for forming the communication ports of sand cores into the recesses opening into cavities. CONSTITUTION:Respective mandrels 12 are fitted onto sleeves 2 and the sand cores 22 are grasped by side walls 101, 102 in a die closing state in the stage of pressure casting. The respective projecting parts 25 of the cores 22 are loosely fitted into recesses 15 to delineate spaces S1 around the parts 25 and the circular conical ends of vent pins 16 face the peak faces of the parts 25. The follow up of the projecting parts is permitted when the sand cores are expanded by a molten metal. The breakage of the projecting parts is thus averaged. The recesses project from the cavities and exist in the upper part of a casting mold and therefore, gases are gathered in the recesses. The gases are passed along the circular conical ends of the vent pins 16, by which the stagnation of the gases is prevented.
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