Screw backpressure controlling method in electric injection molding machine

摘要

The electric injection molding machine comprises a sensor 21, servo motor 15, a motor 23 and a controller 30 and, in a plasticizing process in which the motor 23 is rotated, the controller 30 performs control by repeating a first process in which the rotation of the servo motor 15 is controlled by a first retreating speed command value 33 to make the screw 13 retreat at a low speed when a screw backpressure signal is smaller than a backpressure set value 31 and a second process in which the rotation of the servo motor 15 is controlled by a second retreating speed command value 34 to make the screw 13 retreat at a high speed when the screw backpressure signal is larger than the backpressure set value 31.