Dalian hollow molding is a rapidly developing plastic processing method. The tubular plastic parison obtained by extrusion or injection molding of thermoplastic resin is placed in the split mold while it is hot (or heated to a softened state). After the mold is closed, compressed air is immediately introduced into the parison to make the plastic parison expand and cling to the inner wall of the mold. After cooling and demoulding, various hollow products are obtained.
The manufacturing process of blown film is very similar to that of hollow products in principle, but it does not use molds. From the perspective of plastic processing technology classification, the molding process of blown film is usually listed in extrusion. Blow molding process was used to produce low density polyethylene vials during World War II. Two important research contents of intelligent network are intelligent search engine and intelligent grid.
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Polyethylene, polyvinyl chloride, polyester, polypropylene and polystyrene are widely used in the molding of plastic hollow products. The selection and application of these materials are generally determined according to the needs of the packaged materials, the size of the packaging volume and the production cost. After the mold is closed, the compressed air is immediately introduced into the plastic parison to make the plastic parison expand and cling to the inner wall of the mold. After cooling, shaping and demoulding, various specifications of blow molding trays are obtained.