| 摘要 |
PURPOSE:To obtain a molded item with little internal strain by a method wherein the dwelling process is controlled by pressure in multiple stages corresponding to the change of the temperature of resin or of a mold. CONSTITUTION:A general purpose temperature sensor 26 is mounted for the measurement of the temperature of injected resin in a movable mold 13. In addition, a supersonic type temperature sensor 27 is mounted on the surface of a mold 11 or 13. When the detected temperature of the temperature sensor 26 or the like coincides with the switching point temperature of a dwelling pressure switching temperature setter 32 in a comparison operation and switching signal output section 31, the section 31 inputs a pressure switching signal 33 to a pressure controlling section 34, to which the pressure corresponding to the detection temperature is inputted from a pressure setting section 35 so as to send the pressure to a pressure control valve 25 in order to control the injection (dwelling) pressure of an injection cylinder 23. Since the dwelling process is controlled on the basis of the resin temperature as described above, the internal strain in a molded item can be prevented from developing.
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