Single Screw Double Die Dead Film Blowing Machine,film blowing machine,PE film extruder,PE film blowing machine,LDPE,HDPE 1. main motor ... adjust the gap of take-up roller 3. material of screw and barrel: 38CrMoAlA Polished with nitrogen Treatment hardness of heat treatment ... : screw HV≥740, barrel HV≥900 depth of hardening:0.6-0.7mm ...