| 摘要 |
PURPOSE:To prevent the titled thick wall parts from the generation of a sink mark, by sending compressed air into the thick wall parts through the piercing orifices of the perforated member provided to a mold to form an air sump in said parts. CONSTITUTION:After a molten resin is injected into a mold 3 consisting of a fixed part 31 and a movable part 32 through an injection molding machine 2, the injection machine signal 86 of an air control means 8 is inputted to a timer 87 and a direction change-over valve 83 is changed over from a position A to a position B. Sebsequently compressed air from an air pump 81 is sent into the piercing orifices 5 of the perforated member 6 embedded in the leading end part (a position corresponding to the recessed part 1a of a knob 1) of the push pin 33 of the mold 3 through an air filter 82, a pressure regulating valve 84 and air passages 7a, 7b to form an air sump 19 in the recessed part 1a of the knob 1 which is, in turn, pressurized outwardly in the air sump 9 to cool and cure the molten resin. |
