| 摘要 |
PURPOSE:To prevent the intrusion of air and the generation of flash and to make quick injection by injecting a molten metal at a high speed while the molten metal is filled up to the parting plane of dies, at a middle speed just before the end of filling the molten metal into a cavity and injecting the molten metal at a low speed thereafter. CONSTITUTION:A solenoid of a valve 37 is energized by a driving signal from a control unit 55 and an oil pressure acts on a hydraulic chamber 19b of a cylinder via a valve 33. On the other hand, the working fluid in a hydraulic chamber 19a is discharged successively through valves 45 and 37. A plunger 21 is pushed up at a high speed and the molten metal in a sleeve 12 is injected at the high speed into the die cavity 3. A sensor 53 detects the molten metal and a valve 39 is opened when the molten metal is filled up to the position of the parting planes 1a, 2a in the cavity 3. The plunger 21 is thereafter pushed up at the middle speed and the molten metal is injected at the middle speed. A valve 41 is opened when the time immediate before ending of the filling of the molten metal into the cavity 3 is detected from the position of the plunger 21. The plunger 21 is then pushed up at the lower speed and the molten metal is pressurized at said low speed.
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