| 摘要 |
PROBLEM TO BE SOLVED: To suppress decrease in pressure in pressurizing regions formed in a cylindrical thermoplastic resin. SOLUTION: The inside of a cylindrical thermoplastic resin 4 extruded into a cylindrical shape from a mold 3 provided on the apex of an extruder is clogged by means of stoppers 5a and 5b and this cylindrical thermoplastic resin 4 is expanded by blowing a compressed fluid into it and the outer peripheral face of this expanded cylindrical thermoplastic resin 4 is pressed on the molding face of a mold fitted on a pair of mold trucks 7 provided on the back of the mold 3 in the molding direction to mold a corrugated pipe 1. The inside of the cylindrical thermoplastic resin 4 is divided into a first pressurizing region 8a and a second pressirizing region 8b adjoining along the molding direction D by means of the stoppers 5a and 5b, and a pressurized fluid 6 is fed into these pressurizing regions 8a and 8b by a definite feeding pressure. |
