High-speed injection molding technology, also known as rapid thermal cycling injection molding technology, the use of this technology can be well copied to any shape of the mold surface, the product surface without melting marks, the surface of the mirror to achieve high brightness; improve plastic strength and surface hardness; Molding to improve the flowability of injection molding, improve product quality and strength; make thick-walled molding injection cycle can be reduced by more than 60%; without subsequent serious environmental pollution spray process, can reduce the process and save energy and materials.
This can directly reduce the cost of plastic products, but also to better protect the environment and the operator's personal health.
High-gloss injection molding process principle:
In the mold clamping and mold clamping process before the mold heating, mold clamping is completed, the temperature reaches the set conditions that the injection.Die injection process to maintain high temperature, so that the plastic injection can be kept in the mold well Of the liquid injection completed, under pressure cooling, the mold cooling treatment, but also can greatly shorten the product cooling time, thereby enhancing production efficiency.
The traditional approach is to use the mold temperature to warm the mold, but the disadvantages of this method are as follows:
1. Can not meet the need of rapid heating and rapid cooling in high-speed injection molding;
2. The heating rate is small, the surface of the product weld can only be reduced and can not be eliminated;
3. As the higher the hardness of the plastic, the poorer the flow, so the hardness of the surface of such a craft can only reach HB level can not meet the actual use needs;
4. When the mold is heated and expanded in temperature, it shrinks when the temperature drops, so that the clamping force is very unstable, easily causing various defects such as dissatisfaction, scorch and internal stress.
In the process based on the development of the steam injection molding technology for the above shortcomings were improved:
1. This technology opens the water pipe in the mold, needs the steam when the temperature rises, passes through the cold water when needs to cool down, after the cooling is finished, can use the compressed air to blow out the residual moisture, in order to guarantee to realize the rapid warming, the cooling;
2. In order to eliminate the maximum weld line marks, watermarks, lack of plastic and other products failure;
3. Due to the large temperature rise to H or even 2H hardness level of plastic, so that products greatly increase the surface hardness;
4. As the pipe is opened inside the mold, only the inner surface of the mold is heated or cooled down, and the overall expansion of the mold is small, thereby reducing various product defects caused by the instability of the clamping force.
To produce high-quality high-gloss products, the need for injection molding machines, molds, temperature control equipment for high-gloss plastic products, as well as boilers, cooling devices and other aspects of cooperation:
1. Plastic machine configuration
① clamping system rigidity is better; due to the entire production process to keep heating and cooling.Therefore, requires the injection molding machine clamping mechanism must be rigid, strength is better, to ensure that the clamping force is accurate and stable, thus ensuring the surface quality of products .
② use a large mold injection molding machine: the use of this process can no longer use gas-assisted injection, the production of the required clamping force will be relatively large.
③ According to the circumstances choose a smaller amount of plastic injection: such as the production of flat-panel TVs, LCD screen frame and other products, do not require a larger amount of plastic injection molding machine in the choice of small injection amount of plastic injection molding machine. The actual weight of the injection molding machine in the amount of the best shot between 30% to 80% .If the machine is too large amount of rubber, rubber material in the barrel long residence time easy to separate, the product surface will produce silver and other defects.
④ Equipped with special screw High gloss plastic used in the production of high hardness, the melt index is relatively low, so the screw plasticization is better. At the same time, the screw shear can not be too large, or plastic will be easily broken down.
2 mold configuration
① the inner surface of the mold requires a very high finish to ensure the surface quality of the product;
② molds to open the pipeline must be reasonable to ensure rapid heating and cooling;
③ mold inside the pipe should be good thermal conductivity;
④ due to the need to keep heating and cooling in the production process, the mold steel selection is better;
⑤ In the process of using special attention to mold maintenance, to ensure dry, clean.
3. Temperature control equipment configuration
① temperature control to be very accurate, which is an important guarantee of product quality
② temperature control equipment to respond very fast to ensure a high production efficiency
4 special plastic
Commonly used plastics are ABS, PC + ABS or PMMA + ABS when producing high surface quality products, among them, ABS has the lowest hardness and PMMA + ABS has the highest hardness up to H or even 2H. However, the higher the hardness, The index is also relatively low. Liquidity will deteriorate, so the appropriate plastic can be selected according to production needs.
Steam-free high-gloss injection molding technology has greatly improved the surface quality and surface strength of products, and can be canceled subsequent spraying or painting process, both to protect the environment and the operator's personal health, and reduce the process, eliminating the need for expensive Secondary processing costs, significantly reduce production costs at the same time, save energy and materials.