| 摘要 |
PURPOSE:To contrive stabilization of a quality by preventing a cavity part of a mold from filling with excessive molten resin, by controlling dwell pressure according to a quantity of a deviation between an actual injection stroke and a preset limiting value of the injection stroke. CONSTITUTION:The inside of a cavity 7 of a mold 6 is filled with molten resin. In this instance, a movement of a screw 3 is detected by a stroke sensor 8. When the detected value exceeds a limiting value preset on an injection stroke limiting value setting instrument 12, the same is detected by a comparator 11. A quantity of a deviation of the same is operated by an arithmetic unit 13 of the deviation after that. Then the quantity of the deviation is multiplied by the preset value preset on a correction value setting instrument 15 and the quantity of correction of dwell pressure is obtained, in an arithmetic unit 14 of the quantity of the correction. The quantity of the correction is added to or subtracted from the preset value preset on the dwell pressure setting instrument 17, in an adding and subtracting instrument 16. Then preset pressure of a solenoid relief valve 10 is controlled by an output signal from the adding and subtracting instrument 16.
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