Jiangyin Suofei Electronic Technology Co.,Ltd. , https://www.suofeiscales.com
Brief Introduction to the Development Status of Domestic Blow Molding Machine
Blow molding is a widely used technique for manufacturing hollow thermoplastic products, such as tubular films and containers. The process involves heating a preform to make it pliable, then inflating it within a mold to take the desired shape. This method is commonly applied in the production of high-speed, high-volume PET and BOPP bottles, typically through a two-step process. In addition, blow molding can be combined with injection molding, resulting in a "blow-in-blow" system that's frequently used for PET container production. Another variation is extrusion blow molding, which integrates an extruder with a blow molding unit, allowing for a broader range of materials and product types, including multi-layer films and various polyolefin containers. These are widely used in food, pharmaceutical, and cosmetic industries.
Hollow container forming machines use either one-step or two-step blow molding processes. The two-step method is ideal for centralized preform production and decentralized bottle manufacturing, while the one-step approach suits beverage companies looking for on-site production. In China, two-step equipment is primarily used by specialized PET bottle manufacturers, whereas one-step systems are popular among beverage giants like Master Kong and Wahaha.
PET bottle blow molding machines come in two main types: rotary and straight. Rotary machines offer higher productivity and speed, but they have complex designs and higher costs. The SBO series from SIDEL in France is a prime example, with models like the SBO24 capable of producing over 20,000 bottles per hour. On the other hand, linear machines, such as those from ASB and AOKI in Japan, are simpler in design but face production bottlenecks, generally not exceeding 6,000 bottles per hour.
Temperature control plays a critical role in ensuring uniform plasticization, directly affecting the quality of the final product. The precision of molds and hot runner systems also significantly impacts the outcome.
Currently, most injection-blowing equipment used in China for PET bottle production is imported, especially for high-speed and large-volume applications. Domestic equipment still lags behind in these areas. Only a few manufacturers, such as ASB, have successfully developed large-capacity PET hot-fill bottle blowing machines using advanced multi-stage blowing techniques.
With the growing adoption of cold aseptic filling technology, a new wave of competition is emerging in the blow molding machine market. Although SIPA's one-step machines have gained strong market presence, particularly at Beijing Huiyuan Juice Factory, two-step systems still hold their place in certain applications.
Extrusion blow molding equipment is more versatile, capable of handling a wide range of materials like PE, PS, PVC, and PC. It accounts for about three-quarters of all blow-molded products on the market. This method can produce small items like eye drop bottles or large containers such as 1,000L trays and ton drums.
In China, extrusion blow molding technology has reached a satisfactory level. For instance, Yaqi’s equipment offers a complete range of extrusion blow molding systems, capable of producing containers under 200L. They have also developed in-mold labeling extrusion blow molding machines, which are widely used in cosmetics and lubricant industries.