Self Adhesive Protective Film is a common plastic product. It is produced by calendering process, extrusion process, blow molding process and other methods. The method of film blowing is to melt the raw material through an extruder to extrude the raw material into a thin tube. Then it is blown with compressed air while it is hot, and then cooled and shaped into a film product. After the material is extruded through plasticization, it is formed into a tube and then subjected to inflation molding, cooling, drawing, and winding. In the blown film forming process, there are three methods of flat blowing, upward blowing, and downward blowing depending on the direction of extrusion and drawing. The three processes of PE self-adhesive film have their own advantages and disadvantages. The flat-extrusion blowing tube is hung on the cooling tube, and the traction is stable, and the footprint is small, the operation is convenient, and the protective film with large folding diameter and thicker thickness is easy to produce; It requires high workshops and high cost. It is not suitable for processing fluid plastics, which is not conducive to the cooling of the protective film and the production efficiency is low. Flat extrusion and downward blowing is beneficial to the cooling of PE self-adhesive film, high production efficiency, and can process plastics with greater fluidity; the disadvantage is that the extruder is higher from the ground and the operation is inconvenient to produce thinner PE self-adhesive film. The flat-extrusion flat-blowing head is centered, simple in structure, uniform in thickness of the PE self-adhesive film, convenient operation, simple in film introduction, and large blow-up ratio; but it is not suitable for processing protective films with high relative density and large folding diameter.