Blow molding process of extrusion film blown machine

Plastic film is an important type of polymer material products. Because it has the advantages of light weight, high strength, flatness, smoothness and transparency, and it is easy to process and low in price, it is widely used. Plastic film can be formed by extrusion blow molding, calendering, casting, stentering and direct extrusion using a slit die. The characteristics of various methods are different and their adaptability is also different. Among them, the calendering method is mainly used for the processing of amorphous polymer materials. The required equipment is complex and the investment is large, but the production efficiency is high, the output is large, and the uniformity of the film is good. The main raw materials of the casting method are mostly amorphous polymer materials. The casting method has a simple process, the film has good transparency, isotropy, and uniform performance, but the strength is low, and a large amount of solvent is consumed, the cost increases, and it is not good for environmental protection. The stentering method is mainly suitable for crystalline polymer materials. Its production process is simple, the film quality is uniform, and the physical and mechanical properties are good, but the equipment investment is large.