METHOD OF CONTROLLING INJECTION OF AN ELECTRICALLY DRIVEN INJECTION MOLDING MACHINE.

摘要

Controlling injection of an electrically driven injection moulding machine capable of sharply increasing the speed of injection even when a cheaply constructed electrically driven injection moulding machine is used. An instruction pulse sequence is supplied to a servo circuit under the condition where the injection servo motor is substantially prevented from rotating by setting to the servo circuit of the injection servo motor a torque limit value (Ts) at which the output torque of the injection servo motor and the resin pressure maintain a balanced state. Then, a deviation between a desired rotational position and the practical rotational position of the injection servo motor reaches a deviation (Fs) in the feed stop position. If the limit on the torque is released at a moment when the deviation in the feed stop position is reached, a large drive current flows into the injection servo motor depending on the practical deviation of position that has increased up to the deviation in the feed stop position, whereby the injection screw is driven with a large torque generated by the injection servo motor and the speed of injection increases suddenly.