Abstract: An improved extrusion structure and techniques for obtaining very high extrusion speeds based upon the use of higher extrusion temperatures and resulting increase in critical extrusion rates. Structure is provided for eliminating back flow of the extrudate, for continuously mixing the extrudate just prior to entering the extruding die, and for controlling the temperature of the extrudate at critical locations along the path of flow.

Abstract: An improved process for manufacturing low density polytetrofluoroethylene insulated cable using a paste type extrudate to form a hollow tube of insulated material extruded about a wire conductor which passes through the extrusion die. As contrasted with earlier methods, the shaped extrudate paste is stretched before removing the extrusion aid substantially at ambient temperature with only residual heat imparted by extrusion by a driven pulley, the peripheral speed of which may be varied in accordance with the speed of the extrudate. With the completion of the stretching, the increased outer surface and porosity of the extrudate permits faster removal of the extrusion aid immediately prior to entering a sintering oven.