What is the difference between mould injection and blow molding?
Generally speaking, the injection molding is the solid core, blow molding is the core body, the blow molding surface is uneven. Blow molding has the air port. Injection molding, or thermoplastic plastic injection molding, is the process of melting the plastic material and injecting it into the membrane cavity. Once molten plastic enters the mold, it is cooled and molded into a shape. The resulting form is often the final product, which is no longer needed before the installation or final product is used. Many of the details, such as the bulge, rib and thread, can be formed in the injection molding process. The injection molding machine has two basic parts: the injection device and the coder that melt and feed the plastic into the mould. The function of the die device is: 1. Remove the product from the injection device before it is injected into the mold and melt it, then control the pressure and speed to inject the melt into the mold. The current injection device has two designs: a screw preplasticizer or a two-stage device, and a reciprocating screw. The screw type preplasticizer USES pre-plasticized screw (first class) to inject the molten plastic injection rod (second level). Screw pre plasticizing unit is constant, the melt quality the advantages of high pressure and high speed, and precise injection volume control (using mechanical thrust device) at the ends of the piston stroke
Blow molding: also call hollow blow molding, a kind of development rapid plastic processing method. Thermoplastic resin by extrusion or injection molding of plastic parison tube, hot (or heated to softening state), put in split cavity, mold closing immediately after ventilation with compressed air within the parison, make plastic parison swell and clingy wall in the mold, the cooling mold release, the products have all kinds of hollow. Blown film manufacturing technology on the principle and hollow blow molding is very similar, but it does not use the mould, from the perspective of classification of plastics processing technology, molding process is usually included in the extrusion of blown film. The blow molding process was used in the production of low-density polyethylene small bottles during world war ii. In the late 1950s, with the development of high density polyethylene and the development of blowing and molding machine, blow molding technology was widely used. Hollow containers can be up to thousands of litres, some of which are computerized. It is suitable for the plastic polyethylene, polyvinyl chloride, polypropylene, polyester, etc., and the empty container is widely used as an industrial packaging container.
Injection molding is used to make the mold and then inject the plastic into the mould. Blow molding is used to make a good plastic moulds after heating softening in the embryo, the embryo within the join high pressure air, thinning of the tensile softening of the embryo, formation and mould the same products. Injection molding can make a very complex plastic product, and you can say what shape you want to make. Blow molding can only make hollow products, such as drink bottles and some tool boxes. The moulds are very expensive and the processing is more expensive. Blow molding and processing are cheaper
The process of injection molding and blow molding is different. Injection molding is the injection + pressure; The blow molding must have the head of the pipe, and the injection molding must have a gate section
