| 摘要 |
PURPOSE:To contrive to stably keep the accuracy of a molded part by a method wherein smooth injection pressure is obtained by eliminating the hydraulic pressure shock developing at the changing-over from injection filling pressure to injection dwell pressure. CONSTITUTION:Molding material, which is kneaded with a screw 4 and melted in a heating cylinder 5, is injected and charged into the cavity of a mold. Injection pressure which is given to an injection cylinder 6 is controlled by actuating a hydraulic mechanism 20 through the application of a CPU10 for process control. Especially, the pressure in the dwell process after the completion of injection filling is controlled weaker and at the same time the development of hydraulic pressure shock at the changing-over of the injection pressure set at a pressure setter 11 is prevented. The working hydraulic pressure of the screw 4 is detected with a pressure sensor 12 so as to input the time-sequent signals of measured value from hydraulic pressure of the injection cylinder 6 to the CPU10. By outputting the set injection hydraulic pressure control signals from the CPU so as to follow up said input signals, the injection pressure is controlled in accordance with the control pattern, which allows no abrupt fall of the injection pressure during the dwell process.
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