Injection molding companies|Introduce five kinds of injection molding
Injection molding companies1. Compression injection molding:
It is an advanced form of traditional injection molding.
Advantages: it can increase the flow length ratio of injection molded parts; use smaller clamping force and injection pressure; reduce material internal stress; and improve processing productivity. 1,
Injection compression molding is suitable for products made of various thermoplastic engineering plastics, such as: large-size curved parts, thin-walled parts, miniaturized parts, optical lenses, and parts with good impact resistance requirements.
2. Exhaust injection molding
The purpose of the "venting" procedure is to allow the volatile and volatile fission products generated during the polymerization-solidification process to emit opportunities. If these gases cannot be discharged from the cavity, the result will be incomplete products or air bubbles in the closed area.
1. When the injection volume reaches about 80%-95%, injection is suspended;
2. Open the mold about 0.1-0.2mm in order to discharge the volatile gas;
3. Clamp the mold twice and inject the remaining injection volume.
3. Low pressure injection molding
The low pressure injection molding process is a packaging process that uses a very low injection pressure to inject hot melt materials into the mold and quickly solidify. The excellent sealing properties of the hot melt materials and excellent physical and chemical properties are used to achieve insulation, temperature resistance, impact resistance, Vibration reduction, moisture-proof, waterproof, dust-proof, chemical resistance and other functions, play a good role in protecting electronic components.
The sensitivity of leather, wood, fiber fabric, PVC/TPO/PUR decorative film requires lower injection pressure.
4. Water-assisted injection molding
Water-assisted injection molding technology is an advanced injection molding process in which part of the melt is injected into the mold cavity, and high-pressure water is injected into the melt through the equipment to finally shape the workpiece.
Due to the incompressibility of water, the front end of the water forms a solid interface, squeezing the inner wall of the product into a cavity, and the front end of the water also plays a role of rapid cooling. Therefore, water-assisted has many advantages that air-assisted can't match. Research and application show that water-assisted can generate thinner and more uniform cavity walls, and the inner wall surface of the flow channel is very smooth. Especially for thick-walled workpieces, the cooling time of water-assisted and air-assisted can be greatly reduced.
5. High-gloss injection molding
The basic process of high-gloss injection molding is to use high-temperature and high-pressure water vapor to quickly heat up the surface of the mold before injection molding, so that the surface temperature of the molding cavity reaches above the glass transition temperature (Tg) of the resin plastic, and then the plasticized The plastic melt is injected into the closed mold cavity. During the injection stage, the mold temperature is kept constant by high temperature and high pressure water vapor. When the injection is finished, the air supply is stopped, the water vapor in the pipe is blown out by the air pressure, and then cooling water is introduced to make the mold. The temperature drops rapidly until it cools and the mold is opened to take out the product.