This extruder ,cylinder and screw rods are made of qulity alloy steel that have been nitrizied and processed in a precision way.Hence it is sound in hardness,durable in corrosion resistance .The specially-designed screw is of sound quality in plasticxing,which helps increase the production capacity.It is blowing the plastic films like low density polythene(LDPE),high density polythene(HDPE) and linear low density polythene(LLDPE).it applied to producing the packing bags for foodstuff ,clothing,rubbish bags and vest ones.