| 摘要 |
PURPOSE:To prevent a vertical line on a surface of a parison from occurring by miniaturizing a head and uniformizing a wall thickness of a molding by a method wherein a gap for giving a wall thickness inside a parison is vertically provided on an outer peripheral part of a core, a gap-clearance volume adjuster is freely vertically movably provided to an outlet of the gap, and a die is freely movably provide in a vertical shaft direction. CONSTITUTION:A core 4 passes through a die 2. An outer peripheral part of the core 4 is worked vertically into a gap 6 for giving a wall thickness inside a parison. A gap-clearance volume adjuster 7 is freely vertically movably provided to an outlet of each gap 6. Then, for fundamental wall thickness-control, a slit 5 between the die 2 and the core 4 is adjusted by vertical movement of the die 2. Partial control for giving a wall thickness is carried out by vertical movement of the gap-clearance volume adjuster 7. That is, when the gap 6 corresponding to a corner angle part of the core 4 is provided to the core 4, and the wall thickness is added inside the parison 15, the corner angle part does not become thin in wall thickness and comes to have a uniform wall thickness. Further, since the addition of the wall thickness is carried out from the inside of the parison 15, a surface quality of a product is not deteriorated. |
