High-gloss injection molding technology is also known as rapid thermal cycle injection molding technology. Using this technology, any shape on the surface of mold can be replicated well, so that surface of product has no melt marks, surface highlights can achieve a mirror effect; improve strength and surface hardness of plastic parts; improve injection fluidity of thin-wall molding, and improve quality and strength of product; reduces injection cycle of thick-wall molding by more than 60%; does not require subsequent spraying processes with serious environmental pollution, which can reduce process flow and save energy and materials.

 

This can directly reduce cost of plastic products, better protect environment and health of operators.

Mold is heated before and during mold clamping. After mold clamping is completed, injection will be performed when temperature reaches set conditions. Mold continues to maintain a high temperature during injection process, so that rubber can maintain good fluidity in mold during injection. After injection is completed, when pressure is maintained and cooled, mold is cooled, which can greatly shorten cooling time of product, thereby improving production efficiency.
Traditional method is to use a mold temperature machine to heat mold, but disadvantages of this method are as follows:
1. Cannot meet needs of rapid heating and rapid cooling in high-gloss injection molding;
2. Temperature rise is small, and weld marks on the surface of product can only be reduced but cannot be eliminated;
3. The higher plastic hardness, the worse fluidity. Therefore, surface hardness of products using this technology can only reach HB level, which cannot meet actual use needs;
4. When mold heats up, it expands when it heats up, and shrinks when it cools down, making clamping force very unstable. It is easy to cause various defects such as product dissatisfaction, scorching, and large internal stress.
Steam high-gloss injection molding technology developed on the basis of this process has been improved for above defects:
1. With this technology, water pipe in mold is opened, steam is passed when heating is needed, and cold water is passed when cooling is needed. After cooling, compressed air can be used to blow out residual moisture to ensure rapid heating and cooling;
2. To eliminate to the greatest extent various product faults such as weld marks, water lines, lack of glue, etc.;
3. Surface hardness of product is greatly improved due to large temperature rise and use of H or even 2H hardness plastics;
4. Since only inner surface of mold is heated or cooled when pipes are opened inside mold, the overall expansion of mold is small, so various product defects caused by instability of clamping force are reduced.
To produce high-quality high-gloss products, injection molding machines, molds, temperature control equipment, special plastics for high-gloss products, as well as boilers, cooling devices, etc. are required:

① Rigidity of clamping mechanism should be good; because temperature rises and falls continuously during the whole production process. Therefore, clamping mechanism of injection molding machine must be rigid and strong to ensure accuracy and stability of clamping force. So as to ensure surface quality of product.
② Choose an injection molding machine with large clamping: When using this process, gas-assisted injection can no longer be used, so clamping force required to produce product will be relatively large.
③ Choose a smaller injection volume according to situation: For example, when producing flat-panel TVs, LCD frames and other products, you do not need a large injection volume. When choosing an injection molding machine, try to choose an injection molding machine with a small injection volume. Actual weight of product is best between 30% and 80% of theoretical injection volume of injection molding machine. If amount of glue injected by machine is too large, glue stays in barrel for a long time and is easy to decompose separately, and defects such as silver wire will appear on the surface of product.
④ Plastic used in production of high-gloss products with a special screw has a high hardness and a relatively low melt index, so screw is required to be plasticized. At the same time, shear of screw should not be too large, otherwise rubber will be easily decomposed.

① Inner surface of mold requires a very high finish to ensure surface quality of product;
② Piping inside mold must be reasonable to ensure that temperature can be raised and lowered quickly;
③ Pipes inside mold should have good thermal conductivity;
④ Since temperature needs to be continuously heated and cooled during production process, steel used for mold should be better;
⑤ Pay special attention to maintenance of mold during use to ensure it is dry and dust-free.

① Temperature control must be very accurate, which is an important guarantee for product quality.
② Response of temperature control equipment must be very fast to ensure higher production efficiency.

When producing products with higher surface quality, commonly used plastics are ABS, PC+ABS or PMMA+ABS. Among them, ABS has the lowest hardness, and PMMA+ABS has the highest hardness, which can reach H or even 2H. But the higher hardness, the lower melt index. Fluidity will become worse, so you can select appropriate plastic according to production needs.
Steam traceless high-gloss injection molding technology greatly improves surface quality and surface strength of product, can eliminate subsequent spraying or painting process, which not only protects environment and health of operators, but also reduces process flow and saves expensive secondary processing costs, which greatly reduces production costs. At the same time, it saves energy and materials.