GAS INJECTION MOLDED PRODUCT AND GAS INJECTION MOLDING METHOD AND APPARATUS

摘要

PURPOSE: To shorten an injection molding cycle time by forming a cavity in a resin by gas and injecting low temp. gas into the cavity from a gas injection device to cool the resin from the interior of the cavity. ;CONSTITUTION: A gas injection device 30 is incorporated in a movable mold 10. A resin is injected into a cavity 20 from a cylinder nozzle and, subsequently, high pressure gas is blown in the resin from a nozzle to form a hollow part 21 in the resin received in the cavity 20. Next, gas whose temp. is lower than that of the high pressure gas from the nozzle is injected into the hollow part 21 from the gas injection device and a changeover valve 26b is changed over to discharge the gas in the hollow part 21 and the hollow part 21 is filled with the low temp. gas from the gas injection device 30. Therefore, the resin in the cavity 20 is cooled from the hollow part 21 and the cooling time of the resin becomes short. Since gas injection can be performed from the cylinder nozzle and the gas injection device 30, an injection molding cycle time can be shortened.;COPYRIGHT: (C)1994,JPO&Japio