Do you know what blow molding is?

Blow molding, also known as hollow blow molding, is a rapidly developing plastic processing method. The tubular plastic blank obtained after extrusion or injection of thermoplastic resin is put into the split die while it is hot (or heated to the softening state). After the mold is closed, the compressed air is immediately introduced into the mold blank to make the plastic blank expand and close to the inner wall of the mold, and various hollow products are obtained after cooling and demoulding. In principle, the manufacturing process of blown film is very similar to hollow products, but no mold is used. From the perspective of classification of plastic processing technology, the molding process of blown film is usually included in extrusion. During the Second World War, blow molding process began to be used to produce low-density polyethylene bottles. In the late 1950s, with the birth of high-density polyethylene and the development of blow molding machines, blow molding technology has been widely used. The volume of hollow containers can reach thousands of liters, and some production has been controlled by computers. Polypropylene is suitable for blow molding, and PVC is widely used in industrial packaging.

According to the parison production method, blow molding can be divided into extrusion blow molding and injection blow molding, newly developed multi-layer blow molding and tensile blow molding.