Blow molding products are hollow; Because injection molding has injection molding mouth, there will be a small part of the product that is not needed quickly after molding, and it will be cut off by youdao process. However, if you carefully observe, you can still find it.
Injection molding is a method in which thermoplastic or thermosetting molding materials are uniformly plasticized in the heating cylinder and then pushed into the mold cavity of the closed mold by plunger or moving screw.
Injection molding is suitable for almost all thermoplastics. In recent years, injection molding has also been successfully used to form some thermosetting plastics. Injection molding of the molding cycle is short, the quality of molding products can be from a few grams to dozens of kilograms, one molding shape is complex, accurate size, with metal or non-metal insert molding products. Therefore, this method has strong adaptability and high production efficiency.
Blow molding: a method by which a hot mold billet closed in a mold is blown and expanded into a hollow product by means of gas pressure, or a tube billet is blown and expanded into a tube film without a mold. This method is mainly used in the manufacture of various packaging containers and tubular membranes.
Any melt index of 0.04~1.12 are relatively good hollow blow molding materials, such as polyethylene, polyvinyl chloride, polypropylene, polystyrene, thermoplastic polyester, polycarbonate, polyamide, cellulose acetate and polyacetal resin, among which polyethylene is the most widely used.
Injection blow molding: injection molding method is used to make plastic into a bottom-type blank, and then the blank will be moved to blow molding mold blown into hollow products.
Extrusion blow molding: it is to use extrusion method to first make plastic into a bottom-type blank, and then move the blank into a blow molding mold to blow hollow products.
Stretch blow molding: stretch blow molding is a kind of biaxial directional stretching blow molding, the method of which is to stretch the mold longitudinally first, and then blow with compressed air to reach transverse stretching. Stretch blow molding can greatly improve the transparency, impact strength, surface hardness and rigidity of products. It is suitable for the blow molding of polypropylene and polyethylene terephthalate ester.
Blown film method: a method for forming thermoplastic films. The system USES extrusion method to squeeze the plastic into a tube first, and then makes it continuously expand to a certain size of tubular film with the help of the air blown into the tube, and then folds and winds into a double-layer flat film after cooling.