METHOD AND APPARATUS FOR MOLDING HOLLOW MOLDED OBJECT

摘要

PURPOSE:To certainly obtain a desired hollow molded object by extruding the excessive resin in a cavity into a resin sump part and increasing or decreasing the volume of the resin sump part corresponding to the molding state of a resin hollow object. CONSTITUTION:For example, when it is detected that the hollow part 110 in a resin is smaller than a desired shape, it is necessary that the resin in a cavity 14 is further extruded toward a resin sump part 18. A driving signal is supplied to a servo motor 88 constituting a volume increasing and decreasing means from a control part and the second screw 92 fixed to a rotary shaft 90 is rotated and a piston 82 is moved in the direction shown by an arrow through the first screw 86 meshed with the screw 92. The volume of the resin sump part 18 is increased and the excessive resin in the cavity 14 is introduced into the expanded part of the resin sump part 18 and the volume of the hollow part 110 formed in the resin in the cavity 14 is expanded.