COOLED THREAD SPLIT INSERTS FOR INJECTION MOLDING PREFORMS

摘要

Thread split inserts used in injection molding bottle preforms of polyethylene terephthalate (PET). Each insert has a curved inner surface. A pair of inserts are mounted in the mold facing each other so the inner surfaces combine to form an opening therethrough. The opening provides the portion of the cavity which forms the neck portion of the preform. Each of the thread split inserts has an enclosed conduit through which cooling fluid circulates to improve cooling and reduce molding cycle time. The cooling fluid conduit has three curved portions which extend around the curved inner surface. Two of the curved portions extend in one plane and the other curved portion of the cooling fluid conduit extends in a second parallel plane.