Method and apparatus for controlling torque of an injection molding machine

摘要

A metering controller capable of making a metering time constant and kneading of resin uniform. A screw torque STRQ(n) is detected and stored at every processing period from a start of metering as reference data. A screw rotational speed command is changed over to a set value at each predetermined changeover position. A present screw torque is detected and subtracted from a corresponding screw torque STRQ(n) of the reference data to obtain a deviation DELTATRQ. A correction amount SROT for the screw rotational speed command is obtained based on the deviation DELTATRQ. The correction amount SROT is added to the set screw rotational speed command SRCMD and thus corrected command is outputted for controlling a servomotor for rotating the screw. A screw retracting speed and a screw retracting position may be adopted as reference data. Since a transition pattern of the screw retracting motion coincides with that in obtaining the reference data, the metering time is made constant.