VERFAHREN ZUM HERSTELLEN EINES THERMOPLASTISCHEN ROHRES MIT EINER GLATTEN INNENFLAECHE.

摘要

A thermoplastic tube having a very smooth interior surface is produced by a method comprising: (1) extruding the thermoplastic tube whilst maintaining the interior surface in a molten state by a heating unit disposed within the area of a first mandrel near the nozzle of an extrusion mold, and (2) sliding the interior urface of the tube onto a second mandrel connected to the front end of the first mandrel through a heat-insulating material and in axial alignment with the first mandrel in a manner such as to bring the interior surface of the extruded tube into contact with the smooth surface of the second mandrel and simultaneously cooling the interior surface of the tube with a cooling medium.