| 摘要 |
PURPOSE: To eliminate a turbulent flow mark and a bent layer structure of a final product by providing resin introducing means for accommodating a plurality of separate resins and separate coaxial cylinder molding means at a die body having a longitudinal axis. CONSTITUTION: A mandrel 56 is arranged in a die head 10 by a pin 62 radially extended via a center of a mandrel sleeve 22. The pin 62 is connected to a rod 64 of an operating cylinder 66 provided at a top of the head 10. The cylinder 66 is provided to axially vertically moving the pin 62 and the mandrel 56 while resin extruding. Thus, a space between the mandrel 56 and a die body 12 is changed, and hence a wall thickness of a parison 58 is hanged. Accordingly, the wall thickness is program controlled while considering a blow-up ratio of the parison during molding so that the wall thickness of the final product becomes uniform. |
