Method of injection-compression molding

摘要

The present invention provides a method of injection-compression molding which employs an injection-compression molding machine. According to the method, molten resin is injected to fill in a mold placed in a closed state at an injection mold opened position of a predetermined mold opening stroke "a", thereafter the mold is pressed for closing and compressing until the mold reaches the final mold clamping position. The method comprises the steps of, based on the correlation between the elongation of a tie bar and an mold opening stroke of the mold in the injection process, detecting the elongation of the tie bar caused by injection pressure from injection starting time to injection completion time; calculating the mold opening stroke based on the detected elongation of the tie bar to advance a movable mold by the stroke which offsets the mold opening stroke, thereby holding the mold at the injection mold opened position of the predetermined mold opening stroke "a".