| 摘要 |
PURPOSE:To obtain a parison suitable for molded products of different sizes easily by a method wherein in a flat die of a blow molding machine equipped with a peripherally arranged slit of a deformed shape, a sectional area of an opening is so set as to obtain uniform pressure loss in a peripheral direction of the peripherally rounding slit. CONSTITUTION:For a flat die 32, a rectangular die housing 32 is composed of upper and lower housing materials 34, 36. A central part of the die housing 32 is hollowed out elliptically, and a core bar 40 of an elliptic transection is arranged. Space between the core bar 40 and the housing 32 is taken as a resin passage 42. A mandrel 44 which expands in a skirt like manner is arranged at a lower part of the core bar 40, and flat loop like resin discharge opening is formed thereby. Then, a projection part 100 is provided on the mandrel 44 on the minor axis side X to narrow the resin passage 42 on the minor axis side thereby. Pressure loss on the minor axis side X wherein melted resin flows easily is equallized in a peripheral direction to pressure loss on the major axis side Y wherein the melted resin is difficult to flow. |
