Extruder Functioning Parameters Modification in PE Recycling

The paper presents the extruder functioning point changing, resulted as the intersection of screw and extrusion head functional characteristics curves, during the processing of a polymeric material recycled many times, in comparison with the same polymeric material - first time extruded. The recycling could modify the slope of the screw characteristic curve. In the paper it is shown the modification of the screw characteristic, at the same screw speed, for a sort of HDPE, at a certain extruding temperature. Similar, there are modifications of the extruder head characteristics curves. So the extruder functioning point becomes quite different as the number of recycling increases, but it has to be situated in the head optimal working field.