| 摘要 |
PURPOSE:To obtain a molded piece excellent in surface state and dimensional precision by a method wherein a looped runner part enclosing the entire circumference of the mold cavity and forming the intermediate portion of the runner is provided on the dividing surface of the mold and gas in the mold cavity is exhausted smoothly as the runner is charged with resin. CONSTITUTION:The fixed mold 12 and the movable mold 14 are provided at the closed position to provide the mold cavity 15 and simultaneously degassing is started by the vacuum pump 24 in the mold cavity 15. Under this state, the looped runner 20 enclosing the entire circumference of the mold cavity 15 is charged with molten resin, resin is supplied to the mold cavity 15 through the runner 17 and when the runner 25 is charged with molten resin, the dividing surface 16 between the mold cavity 15 and the external space is interrupted completely by said resin. Therefore, the suction force of the vacuum pump 24 acts effectively on the mold cavity 15, the air in the mold cavity 15, the volatile gas in the resin are absorbed and exhausted efficiently externally from the degassing passage 22. |
