| 摘要 |
PURPOSE:To uniformize strength of a stack mold by molding preforming body having enlarged size upward more than the desired shape at upper face part of the mold, making the desired shape of this by compression and further raising/lowering a plug pattern. CONSTITUTION:At the time of molding the lowest mold, a blowing mold 15 is inserted into recessed part 4 in lower mold 5 and a cavity, in which the upper face part is enlarged upward more than the desired shape of the mold. A sprue rod pattern 9 is inserted, and by packing green sand into the cavity, the preforming body is molded. The lower mold 5 is lowered to separate the blowing mold 15, and a compressed mold 22 is shifted between the lower mold 5 and the blowing mold 15, and the lower mold 5 is raised. In the case of molding the most upper mold, the plug pattern 23a is lowered to attain plugging state of the recessed part 23. Raising of the lower mold 5 is continued and the upper face of the preforming body is abutted on the lower face of the compressed mold 22 and the upper face of the compressed mold 22 is abutted on the lower face of the blowing mold 15. By this method, the compressed mold 22 is relatively inserted into the recessed part 4 of the lower mold 5, and the preforming body is compressed to the shape of the desired mold.
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