Apparatus for valve-gate injection molding and method for the same

摘要

An apparatus for valve-gate injection molding producing an annular molded product having a center through-hole has a valve gate with a simplified structure. The apparatus includes a movable mold member having a first center bore extending in an axial direction, a stationary mold member having a second center bore corresponding to the first bore and providing a product cavity forming the annular molded product between the mold members, a nozzle mounted on the stationary mold member and having a resin supply route having an opening communicating with the second bore, a valve pin extending in the resin supply route and movable between a closing position for closing the opening and an opening position for opening the opening, a center pin movably arranged in the first bore and having a tip surface in contact with a tip surface of the valve pin, and a driving mechanism driving the center pin in the axial direction.