NOZZLE TOUCH DEVICE FOR INJECTION MOLDING MACHINE.

摘要

A nozzle touch device cycle includes a guide rod which is integral with a ball nut meshing with a ball screw connected to a servo motor and which passes through a hole bored in an extension of an extruder base of an injection unit. A spring is fitted over the guide rod and interposed between the ball nut and the extension. A servo circuit to which a signal, representing an actual nozzle touch force from a strain gauge is disposed on the extension and a signal representing a predetermined nozzle touch form a numeric controller are supplied. The servo circuit drives the servo motor in accordance with the difference between these signals to move the guide rod, and compresses the spring to a compression state where an actual nozzle touch force in conformity with the predetermined nozzle touch force is generated. Deformation of the mould at the time of mould opening is prevented by changing the predetermined nozzle touch force to a smaller value at the time of shift from mould closing to mould opening.