| 摘要 |
PURPOSE:To produce a molding having no defects such as recesses by the stagnation of gas by bringing a shielding film having many vent pores into tight contact with a master pattern member and packing a granular packing material to the outside thereof in a molding flask then attracting the shielding film toward the granular packing material side by a negative pressure, parting the master pattern member, pouring a product material into the cavity made after parting and curing the material. CONSTITUTION:The PE shielding film 2 having the many vent pores is brought into tight contact with the surface of the master pattern member 1 formed of a wooden pattern, etc. Such member is held in place between a pair of the upper and lower molding flasks 3 and 3 and the granular packing material 6 is packed into the flasks 3. The entire part is tentatively fixed by a retaining flask 4 an the inside of the flask is evacuated to the reduced pressure through pipes 5 provided to the flasks 3 to compact the packing material. The upper and lower flasks are then separated and after the master pattern member 1 is taken out, both flasks 3, 3 are joined. An expandable resin liquid 9 such as polyurethane stock is put into the cavity 8 corresponding to the master pattern member and is cured to fashion a polyurethane molding 10. The gas generated in this stage is vented through the vent pores of the shielding film. The product 10 having no defects by the stagnation of the gas is thus produced at a good yield. |
