Hollow blow molding process details

Author: MULAN - Plastic Molding Manufacturer

The general principle of hollow blow molding is to blow compressed air into the molten parison to make it blow laterally, cling to the surface of the mold cavity, and become a hollow product after cooling. According to the different manufacturing methods of the parison, it can be divided into injection molding and blow molding. molding, extrusion blow molding, injection stretch blow molding, extrusion stretch blow molding and multi-layer blow molding, etc. hollow blow molding Hollow blow molding is a process in which the semi-molten plastic parison obtained by extrusion or injection molding is inflated by compressed air in a closed mold, and then cooled to obtain a hollow part. The whole process is mainly divided into three steps, namely, the manufacture of the parison, the hot-melt inflation of the parison and the cooling and shaping of the product. According to the different production methods of the parison, it can be divided into two categories: extrusion blow molding and injection blow molding. In addition, adding longitudinal stretching before the hot-melt parison is inflated can be derived: extrusion-pull-blow process and injection -Pull-blow process. Hollow blow molding has simple processing technology, low energy consumption, high production efficiency, and can be mass-produced; the products are diverse, and thin-walled containers such as beverage bottles can be produced. The main application market of hollow molding products is used as packaging materials for food, beverages, daily chemical products, medicines, and cosmetics. Packaging of raw materials and products for industrial and agricultural production. Almost all thermoplastic resins can be used in the manufacture of hollow blow molded products, among which the most important resins are polyethylene and polyester. PVC and polypropylene etc. The main equipment and structure of the extrusion blow molding process are divided into: extruder, parison extrusion die, product mold and mold clamping device, etc.