| 摘要 |
PROBLEM TO BE SOLVED: To suppress generation of a warpage and to surely and remarkably shorten cooling time even when a thick and large hollow molded article with a curved part and a corner is molded by means of a hollow injection molding process. SOLUTION: A molten resin and a pressurized gas are injected into a mold cavity 2. After the mold cavity 2 is filled with a resin with a hollow part 13 filled with the pressurized gas, an on-off valve 4 between the mold cavity 2 and a sacrifice cavity 3 is opened, and a gas vent hole 15 is formed by breaking a part of a resin wall of the periphery of the hollow part 13 by a pressure difference between the hollow part 13 and the sacrifice cavity 3, and injection of the pressurized gas into the hollow part 13 and vent of the pressurized gas from the gas vent hole 15 are performed to cool the molded article by an adiabatic expansion effect of the pressurized gas. |
