Patent ID: 6682689
Filing Date: 2004-01-27
Classification: B29B,B29C,B29L,F16J,F16L

Abstract:
A process for making a plastic tube having a variable diameter comprising the steps of:(a) obtaining a plastic; (b) feeding said plastic into an extruder die; (c) extruding said plastic as a tubular molten plastic stream into a mold cavity having an inside diameter greater than the diameter of the tubular molten plastic stream, the mold cavity inside diameter varying longitudinally along the length of the mold cavity; (d) vacuum expanding the tubular molten plastic stream radially against the mold cavity inner wall; and (e) continuously varying the wall thickness of the tubular molten plastic stream to form alternating thicker and thinner regions during extrusion at multiple successive locations longitudinally along the stream.