BLOW MOLDING APPARATUS AND METHOD WITH PARISON UNIBLOW MOLDING APPARATUS AND METHOD WITH PARISON UNIFORMITY AND ALIGNMENT CONTROL FORMITY AND ALIGNMENT CONTROL

摘要

08CT05349 A blow molding apparatus and method in which a substantially stress reduced parison is formed by extrusion means which provides for a substantially uniform process condition history around the periphery of the parison and in which means are provided for enhancing the structural rigidity of the parison to prevent sagging and buckling of the parison and maintain alignment thereof with the longitudinal axis of the extrusion die as the parison is elongated from the die, and for further maintaining alignment of the parison with the axis during the blow molding operation to form a stress reduced container having a substantially uniform wall thickness. In one embodiment, the structural rigidity of the parison is enhanced by cooling the outer surface thereof to form a thin outer surface region of higher viscosity material on the heated parison.