| 摘要 |
PURPOSE:To reduce internal distortion of a molded product by setting retained pressure at zero and completing a pressure retaining process at which the temperature sensed by a temperature sensor provided on a mold becomes equal to a predetermined value of the pressure retaining end temperature. CONSTITUTION:A pressure control section 3 controls the amount of opening and closing of a pressure control valve 4 based on a program set by time in the initial stage of 9 pressure retaining process after the completion of injection filling, and the initial retained pressure P0 changes to P1 at the point of time t1 and further changes to P2 at the point of time t2. Apart from the advancement of the program, the mold temperature is sensed by a temperature sensor 5. As the time goes on, the resin temperature falls gradually, and a pressure retaining end signal 9 is outputted when a signal which is produced by amplification on conversion of the temperature sensed by the temperature sensor 5 coincides with a signal corresponding to a predetermined value T of the pressure retaining end temperature as a result of comparison and the pressure control section 3 controls the pressure control valve 4 to make the retained pressure zero. |
