| 摘要 |
PURPOSE:To constitue the above method so that at the time of injection molding of a molded product having a hollow part, gas in the hollow part can be discharged as a gas nozzle is fixed and at the time of cutting-off of a gate part before mold break, the cutting-off of the gate part can be performed at the optimum timing. CONSTITUTION:Molten resin is injected within a molding cavity 5 through a gate part 7 and then a fixed quantity of gas is injected into a mold cavity through the gate part 7 by a fixed pressure, through which a hollow part Wa communicating with the gate part 7 is formed in a specific part of the resin filled into the molding cavity 5, then the gate part 7 is cut off, the gas in the hollow part Wa is released and then mold break is performed. Then a pressure sensor 18 capable of detecting injected gas pressure is provided and cutting-off timing of the gate part 7 is controlled based on a detected value of the sensor 18. |
