Abstract: Carriage assembly mounted molds are paired along a production system axis at a receiving region. Each carriage assembly is configured with an axially inwardly depending threaded connector nut configured to engage a translational screw moving the mold sets in registry about an extrusion die to establish a dynamic forming tunnel. Each mold of a mold set is configured having an internal mold cavity with mold crests spaced apart to define a sequence of vacuum support regions. A sequence of annular insert components are positioned over the vacuum support regions to form mold cavities and to define vacuum cavities.

Abstract: Die apparatus configured for forming corrugated pipe from thermoplastic material in association with transported wall mold sets defining a wall forming tunnel. The apparatus employs two homogenizer stations, a first at its entrance for providing homogenized material to an outer wall delivery channel extending to an outer wall extrusion nozzle. Plastic material is delivered under pressure along a heated internally disposed extender pipe to a liner homogenizer stage located downstream and feeding a liner extrusion nozzle. An access region is made available between the outer wall extrusion nozzle and the liner extrusion nozzle.