Blow molding mainly refers to hollow blow molding (also known as blow molding), which is a method for inflating a hot-melt parison closed in a mold to form a hollow product by means of gas pressure, and is a plastic forming method which develops faster. The mold for blow molding has only a female mold (female mold). Compared with injection molding, the equipment has lower cost, strong adaptability, good formability (such as low stress), and can form products with complex undulating curves (shapes).

The most commonly used raw materials for blow molding include polyolefins such as PE, PP, PVC, and engineering plastics such as PA and PC. The electric power includes elastomers. Among them, PE plastics are the most used. The blow molding process can be used not only for forming bottles of various sizes and shapes, liquids and medicines, children's toys, thermos bottles, etc. in daily life and industry, but also for molding hollow industrial parts of various shapes, especially It is a component of the automotive industry. The application range of blow molded products involves automobiles, office equipment, household appliances, medical equipment, entertainment equipment, and furniture. Among them, the automobile plastic fuel tank is the largest hollow blow molding automobile component produced recently. It started production in 1973 and has occupied 90% of the total automobile fuel tank by 2000. In recent years, blow molding technology has developed even faster, from single-layer blow molding to double-layer and multi-layer blow molding. Blow molding processes have emerged from extrusion blow molding, injection blow molding, and extrusion or injection stretch blow molding. Computer simulation technology has also played an increasingly important role in the blow molding process, and computer CAE/CAM technology has become increasingly mature. The blow molding process is geared towards the production of larger and more diverse hollow products with faster production speeds and higher quality.