| 摘要 |
PURPOSE:To obtain a resin molded piece having no sink mark on its surface, a molding method therefor, and a molding device therefor by a method wherein expanded cells and a hollow part are formed in a thick-wall part of an injection molded piece. CONSTITUTION:A movable or stationary mold is provided with a supply means (an air compressor 51, an N2 gas bomb 62, a solenoid change-over valve, and the like) for supplying a compressed air to a cavity 2 and a high-pressure gas injection means (a gas injection nozzle 5, an N2 gas bomb 11, a reserve tank 19, a diaphragm pump 28, a high-pressure reserve tank 32, injection gas pressure setting circuits 36A, 36B, 36C, and the like). The compressed air is supplied to the cavity 2. A melt resin with an expandable gas melted is injected into the cavity 2. After that, a high-pressure gas is injected into a molded piece for a predetermined time, and the compressed air and the high-pressure gas are discharged. A hollow part is formed in a rib part. A thick-wall part is interspersed with expanded cells in a surface layer and in the hollow part or to the hollow part. In this manner, the molded piece having no sink mark on its surface can be obtained. |
