Apparatus and method for automatically controlling an extruder for thermoplastic material

摘要

There is described herein a method of operating an extruder for thermoplastic material to automatically control the output of the extruder. The extruder includes a kneader screw, a hopper having a feed screw for feeding the thermoplastic material in dry particulate form to the kneader screw and an outlet feed screw for removing the plastic material in molten form from the kneader screw. Each of the screws is operated by a separate electric motor. The method includes monitoring the current of the motor for the kneader screw. Variations in the current indicate variations in the opertion of the kneader screw. Upon any variation in the current of the kneader screw motor, the speed of the hopper feed screw and/or the outlet feed screw is varied to compensate for the variation in the operation of the kneader feed screw and return the current to its original value.