FLAT DIE FOR BLOW MOLDING

摘要

PURPOSE:To improve the operation rate of a molding machine by injecting uniformly a flat parison to achieve the cost reduction of products by designing the cross section of an opening to make the pressure loss uniform along the circumference of a ring-shaped resin passage which changes from a circlular to an elliptic form as resin descends. CONSTITUTION:A core 16 is inserted into a die housing 12 to form a resin passage 18, to which an inlet 22 for resin flow from an extruder is opened at a corresponding position. The resin passage 18 branches right and left in the circumferential direction on the surface from the inlet 22 to the core 16 to reduce its cross section, and a manifold 24 is formed which is warped in the extrusion direction. One end of the manifold 24 is combined with the other end of the manifold 24 from the inlet 22. The cross section of the ring-shaped resin passage 18 is formed to change from circle to ellipse as resin descends from its upper part. The cross section of the opening is designed to make the pressure loss uniform along the circumference of the resin passage 18.