| 摘要 |
PURPOSE:To vent gases from core print parts effectively and to prevent the blow hole defects of products by providing recesses in the parts for supporting the core print of a casting mold, and punching many vent holes in shielding films for air permeation facing said recesses. CONSTITUTION:Recesses 9 are made at the center in the supporting parts for the core print 7 of a master mold 8, and vent holes 6' are punched in the vinyl films is facing said recesses 9. In the stage of inserting a core, the holes 6' remain without closed; at the same time, a core 5 can be supported firmly. The recesses 9 to be made in the mold 8 are provided by providing projections 10, 10' in the middles of the side faces 7a, 7a' of the core print in the stage of manufacturing the casting mold, providing projections 11 at approximate center of a end face 7b and a bottom face 7c, transferring the same to the shielding films for air permeation 1 in the stage of suction molding, and using the core print 7 parts having no projections, 10, 10', 11' in the stage of setting the core 5. |
