its extruder, cylinder and screw are made of quality alloy steel with optimum hardness and strong corossion resistance after nitrogen treatment and precsion processing. The specially designed screw enhances plasticizing of film, which helps increasing the production capacity, lt is applied to blowing the plastic films like low density polvethylene LDPE),hich density polvethylene (HDPE) and linear low density polvethylene (LLDPE),lt is widelv applied to producing the packing bags for foodstuff, clothing, rubbish and so on.