| 摘要 |
PURPOSE:To promptly prevent resin from over-filling in a mold by a method wherein the variation is detected by comparing the normal resin injection position of the screw of an injection molding machine with the injection position under the abnormal advance of the screw. CONSTITUTION:During injection, pressure oil is fed by means of an oil hydraulic motor 8 from an oil tank 7 through an solenoid controlled selector valve 9 to the chamber 6a of an injection cylinder 6 so as to advance a screw 1 through a ram 10 in order to inject molten resin stored in a space 5 at the tip of a cylinder 4 and consequently to obtain a molded piece 13. At this time, if the screw 1 advances beyond the range of the predetermined amount (l) for cushioning, the ovaer-advanced state of the screw 1 is detected by a position detection digital linear scale 17, which issues a signal to control device 18. Upon receipt of said signal, the control device 18 changes the solenoid controlled selector valve 9 and stops the supply of pressure oil from the oil hydraulic motor 8 to the chamber 6a of the injection cylinder 6, resulting in stopping the advance of the screw 1. Consequently, the over-filling of resin in a mold 12 is stopped promptly. |
