1. Injection molding and blow molding process is not the same, the blow is the injection + blow; injection is the pressure + injection; blow must do pull the trachea left the head, the injection must do have a gate section.
2. In general, injection molding is a solid core, blow molding is hollow core body, blow molding surface is not smooth.
3. Injection molding, that is, thermoplastic injection molding, this method is to melt the plastic material, and then injected into the cavity. Once the molten plastic enters the mold, it is cold-formed into a shape by the mold cavity. The resulting shape is often the final product and no further processing is required until it is installed or used as a final product. Many details, such as protrusions, ribs, threads, can be molded in a one-shot injection molding operation. The injection molding machine has two basic components: the injection unit and the mold clamping unit for melting and feeding the plastic into the mold.
The role of mold and device is:
A, so that the mold withstand the injection pressure closed;
b, the product is taken out of the injection device to melt the plastic before it is injected into the mold, and then the pressure and speed are controlled to inject the melt into the mold. There are two designs of injection devices currently used: screw pre-plasticizers or two-stage devices, and reciprocating screws. The screw pre-plasticizer uses pre-plasticized screw (first stage) and the molten plastic into the injection rod (second stage). The advantages of screw pre-plasticizers are constant melt mass, high pressure and high speed, and precise injection volume control using mechanical thrust devices at both ends of the piston stroke. These strengths are required for transparent, thin-walled products and high production rates. Disadvantages include uneven residence time (leading to material degradation), higher equipment costs and maintenance costs. The most common reciprocating screw injection unit melts and injects plastic without the need for a plunger. The company is located in:
4. Blow molding: also known as hollow blow molding, a rapid development of plastic processing methods. Thermoplastic resin extruded or injection-molded tubular plastic parison, hot (or heated to a softened state), placed in the mold, the mold closed immediately after the introduction of compressed air in the parison, the plastic parison blow Expansion and close to the mold wall, after cooling demoulding, that is, a variety of hollow products. Blown film manufacturing process in principle and the hollow product is very similar to the blow, but it does not use the mold, plastic processing technology from the classification point of view, the blown film molding process is usually included in the extrusion. During the World War II blow molding process began to be used to produce low-density polyethylene vials. The late 50′s, with the birth of high-density polyethylene and the development of blow molding machines, blow molding technology has been widely used. Hollow container volume up to thousands of liters, and some production has been using computer control. Suitable for blow molding of plastic polyethylene, polyvinyl chloride, polypropylene, polyester, the resulting hollow containers are widely used as industrial packaging containers.
Post time: Mar-14-2018