Blow mold
Hollow forming of plastic is a hollow container with compressed air and a hollow container with a vacuum suction. Blow molding hollow containers are mainly used for the manufacture of thin-walled plastic bottles, barrels and plastic parts. Plastic suction hollow container is mainly used for manufacturing the thin wall plastic packaging supplies, cups, bowls and other disposable containers. Hollow blow molding is the plastic parison in the mold plastic state within the compressed air into the parison, blow up, blow up after the shape of the mold cavity products in the same shape, cooling after get the products. According to the different forming methods can be divided into extrusion blow molding, injection blow molding, injection stretch blow molding, multi-layer blow molding, sheet blow molding and so on.
Extrusion blow molding
Extrusion blow molding is the main method of forming hollow plastic parts. The first extruder tubular billet; interception of a tube while hot into the mold, the mold and the clamping closed open parison on the upper and lower ends; the cavity to pass into the compressed air, the expansion cavity wall attachment and forming, and then packing; finally after cooling, can be excluded the compressed air and remove the plastic mold. The extrusion blow molding die has the advantages of simple structure, less investment and easy operation, which is suitable for the hollow blow molding of various kinds of plastic. The disadvantage is that the wall thickness is not easy to be uniform, and the plastic parts need to be processed to remove the fly edge.
Injection blow molding injection molding injection molding is made of injection molding machine in the injection molding process, and then the heat into the hollow blow molding die hollow blow molding. The first injection molding machine in injection mold into the molten plastic parison; core and parison together into the blow mold, the core is hollow and wall with holes; pass into the compressed air from the mandrel pipe, the parison blowing up and cavity wall affixed to the mold; packing and cooling after setting the compressed air is discharged, and remove the plastic mold. After the injection blow molding plastic parts with uniform wall thickness, no flash, no processing, by stem injection parison bottom, so the bottom and no spell seam, high strength, high production efficiency, but the price of expensive equipment and die, for mass production of small plastic parts.
Injection stretch blow molding
Comparison of injection stretch blow molding and injection blow molding, the extension of this process is increased. The first injection of a hollow billet type bottom; parison moves to stretch and stretch blow molding station; blow molding, pressure; after cooling to remove the plastic mold. There is another kind of injection stretch blow molding method, cold forming method, injection stretch blow molding parison and plastic forming are performed in different equipment, after parison injection is completed, and then moved to the blow molding machine for blow molding, the parison has distributed some heat, the need for two to heating. Ensure the stretch blow molding parison forming temperature, the main characteristic of this method is relatively simple structure of equipment。
