PRODUCTION OF SYNTHETIC RESIN PIPE

摘要

PURPOSE:To efficiently and certainly produce a product excellent in accuracy. CONSTITUTION:In producing a synthetic resin pipe by a process allowing a tubular molten resin to flow out of an extrusion mold 2 and holding and shaping the inner surface of the formed molten pipe member 3 by the auxiliary mandrel 3 provided so as to protrude from the mandrel 21 of the extrusion mold 2, a spiral pleated part 41 is formed to the outer peripheral surface of the auxiliary mandrel 4 and the inner surface of the molten pipe member 3 is held and shaped through the pleated part 41. The pleated part 41 is formed by cooling piping 40 permitting a cooling medium to pass to cool the inner surface of the molten pipe member 3 simultaneously with the holding pipe member 3 due to the auxiliary mandrel 4.