Plastic raw materials injection molding, six plastic raw materials injection molding methods
Click： Time：2018-10-08 11:41:06
First, compressed plastic material injection molding
Compression plastic injection molding is a more traditional way of injection molding of plastic materials;
Principle:
First inject the melt into the mold cavity, when the melt into the mold lungs. Mold in its pressure knife under the open a little; to be full of molten material after the cavity, and then use high pressure to lock the mold to get the required products. The second step is to press molding. As the melt has been in the mold has been a small amount of open state into the cavity, it is required to allow the mold force is small. In the molding screw is no longer injected into the cavity, but by high pressure to lock the mold and thus the force Lf pressure on the plastic and molding, and thus the product orientation is small, low internal stress. This method is especially suitable for molding products with small volume and high transparency requirements;
Advantages.
It can increase the flow length ratio of the plastic material injection molded parts; the use of smaller clamping force and plastic material injection pressure; reduce the internal stress of the material; and improve the processing productivity.
Injection compression molding is suitable for a variety of thermoplastic engineering plastics products; such as large-size curved parts, thin-walled, miniaturized parts, optical lenses, as well as good impact resistance requirements of the parts.
Second, exhaust plastic material injection molding
Principle:
When the plastic injection volume reaches about 80% -95%, plastic injection suspension; the mold open about 0.1-0.2mm in order to volatile gases out; the second mold, and plastic injection of the remaining plastic injection volume.
Advantages:
Gas-assisted injection molding parts injection pressure is lower, you can choose a lower clamping force of the equipment molding larger parts.
Third, low-pressure plastic material injection molding
Principle.
Pressure plastic material injection molding process is a very low plastic material injection pressure will be injected into the mold of hot melt material and fast curing encapsulation process, to the hot melt material excellent sealing and physical and chemical properties to achieve insulation, temperature resistance, impact resistance, vibration damping, moisture, waterproof, dust, chemical corrosion resistance and other efficacy of the electronic components to play a good role in protecting.
Advantages:
Low-pressure plastic injection molding process of low-pressure plastic materials, low equipment costs;
Fourth, gas-assisted injection molding of plastic materials
Plastic raw materials injection molding stage (part) - inflatable stage (N2) - gas pressure stage (cooling gas pressure remains unchanged) - pressure reduction stage - demolding stage
Advantages:
Gas-assisted plastic injection molding technology has a lot of incomparable advantages, it not only reduces the manufacturing cost of plastic products, but also to improve some of its performance; in the case of parts to achieve the same use requirements, the use of gas-assisted plastic injection molding can greatly save plastic raw materials, the savings rate can be as high as 50%, on the one hand, the reduction in the amount of plastic raw materials brought about by the reduction of the entire molding cycle of the various links in the reduction of time On the one hand, the reduction of plastic raw material consumption brings about the reduction of time of the whole molding cycle;
Fifth, water-assisted injection molding of plastic materials
Water-assisted plastic injection molding technology is part of the melt into the mold cavity, through the equipment will be injected into the melt of high-pressure water, and ultimately make the workpiece molding of an advanced plastic injection molding process.
Advantages:
Due to the incompressibility of water, thus the front end of the water to form a solid interface, the inner wall of the product is squeezed into the cavity, the front end of the water at the same time also play a role in rapid cooling. Therefore, water-assisted has a lot of gas-assisted incomparable advantages, research and application shows that the water-assisted can generate a thinner and more uniform cavity wall, and the surface of the inner wall of the flow channel is very smooth. Especially for thick-walled workpieces, water-assisted compared with gas-assisted cooling time can be significantly reduced.
Six, high-gloss plastic raw materials injection molding
Highlight the basic process of injection molding is in the injection molding before, through the use of high temperature and high pressure water vapor to the mold surface rapid heating, so that the molding cavity surface temperature reaches the glass transfer temperature of the resin and plastic (Tg) above, and then proceed to plasticize the plastic melt into the closed mold cavity, the injection stage, the mold temperature by the high temperature and high pressure steam to maintain the same when the injection is completed, the stopping of the gas supply, by air When the injection is finished, the gas supply is stopped and the water vapor is blown out of the pipeline by air pressure, after which the cooling water is passed in to make the temperature of the mold drop rapidly until it cools down and the mold is opened to take out the product.
Advantages:
Compared with ordinary injection molding, it has the ability to effectively eliminate the defects such as fusion line, ripple, silver wire pattern and floating fiber on the surface of the product, improve the quality and strength of the product, and completely solve the traces on the surface of the product;
