Topic Tag: extrusion HDPE

Hi guys, can anyone tell me what is happening to my HDPE upon extruding? It looks chafed or scaly? Sometimes It only happens in the beginning of extruding, then it goes away, then comes back, very inconsistent. I have 160º on nozzle and 170º on barrel. My first guess is that it is getting burned but I have experimented by lowering the temperature with no change. It appears to happen more when color is being changed and mixed or if it is left in the barrel too long. On certain colors there is no issue but with sometimes with certain colors it happens. Has anyone experienced this before? Thanks!