Approach to the solution for removing “sharkskin” of PE pipe through extruder die modification [PE]

Key words : shark skin, extrusion, die head, polyethylene pipe It was found that the ratio between the length of the land of the extruder head (L) and the gap between the die and the mandrel (T) has an effect on the pipe appearance during extrusion process. The present paper discusses the relevance between shark skin and L/T value. Experiment shows that an increase in L/T value can avoid occurrence of shark skin in the process of pipe extrusion.