The extruder, barrel, and screw of this unit are made of high-quality alloy steel, which has undergone nitriding treatment and precision processing, and has the best hardness and corrosion resistance. The specially designed screw has a high output and good plasticization. Suitable for blowing low density polyethylene (LDPE), high-density polyethylene (HDPE), linear low density polyethylene (LLDPE) and other plastic films, widely used in civil and industrial packaging such as food, clothing, garbage bags, vest bags, etc. Adopting a double-layer structure mold and a high-speed structure screw.