| 摘要 |
PROBLEM TO BE SOLVED: To enhance the smoothness of the outer surface of an inner and outer surface smooth pipe. SOLUTION: In a method for manufacturing the inner and outer surface smooth pipe by applying a synthetic resin strip material 4 to the outside of a synthetic resin pipe 1 having a smooth inner surface and having ridge parts 2 and trough parts 3 spirally formed to the outer peripheral surface thereof, in antipitation of the shrink quantity caused by cooling of the synthetic resin strip material 4 spirally wound around the synthetic resin pipe 1, the formula: W=WH+(WL-WH)×(1.25±0.10) (wherein W is the width of the synthetic resin strip material 4 extruded from an extruder, WH is the width of the ridge parts 2 of the synthetic resin pipe 1 and WL is the width between the centers in the width direction of the adjacent ridge parts 2 and 2) is satisfied. |
