The blow molding products are all hollow; because of the injection molding port, the molded product will have a small and unnecessary part, and there will be a process to cut it off, but if you look carefully, you can still find it;
Injection molding (injection molding) is a method in which a thermoplastic or thermosetting molding compound is uniformly plasticized in a heating cylinder and then pushed by a plunger or a moving screw into a cavity of a closed mold.
Injection molding is suitable for almost all thermoplastics. In recent years, injection molding has also been successfully used to form certain thermoset plastics. The molding cycle of injection molding is short (several seconds to several minutes), and the quality of molded products can range from a few grams to several tens of kilograms. It can form moldings with complex shapes and precise dimensions, with metal or non-metal inserts. Therefore, the method has strong adaptability and high production efficiency.
Blow molding: A method in which a hot parison closed in a mold is inflated into a hollow product by gas pressure, or a tube parison is inflated into a tube film. This method is mainly used for various packaging containers and tubes. Film manufacturing.
Any melt blown index of 0.04~1.12 is a relatively good hollow blow molding material, such as polyethylene, polyvinyl chloride, polypropylene, polystyrene, thermoplastic polyester, polycarbonate, polyamide, cellulose acetate and poly Acetal resin, etc., which is most widely used in polyethylene.
(1) Injection blow molding: The plastic is first made into a bottomed parison by injection molding, and then the parison is moved into a blow mold to be blown into a hollow product.
(2) Extrusion blow molding: The plastic is first made into a bottomed parison by extrusion, and then the parison is moved into a blow mold to be blown into a hollow product.
(3) Stretch blow molding: Stretch blow molding is a blow molding of biaxially oriented stretching by first stretching the form longitudinally and then inflating with compressed air to achieve transverse stretching. Stretch blow molding can greatly improve the transparency, impact strength, surface hardness and rigidity of the product. It is suitable for blow molding of polypropylene and polyethylene terephthalate (PETP).
(4) Blown film method: A method of forming a thermoplastic film. The plastic is first extruded into a tube by extrusion, and then continuously expanded to a certain size of the tubular film by air blown into the tube, after cooling. Folded and wound into a double flat film.