High light injection molding technology for plastic products

With the improvement of living standards, people have higher and higher requirements for the appearance of goods. The appearance of many electronic products has become an important standard for consumers to choose goods.
How to produce no fusion marks, no flow marks, no flow lines, no shrinkage marks, surface high-light shell products, for flat panel TV, computer LCD display, air conditioning, automotive interior parts is particularly important. The use of high light injection molding technology can be a good solution to this problem.

01

The process principle of highlight injection molding

The mold is heated before and during the mold closing process, and injected when the temperature reaches the set condition after the mold closing is completed. The mold continues to maintain high temperature during the injection process, so that the rubber material can maintain good fluidity in the mold when injected. When the injection is completed, the mold is cooled when the pressure is kept and cooled, and the cooling time of the product can be greatly shortened, thus improving the production efficiency.

Steam seamless highlight injection molding

This technology is still an advanced production process in China. Because this technology greatly improves the surface quality and surface strength of the products, and can cancel the subsequent spraying or painting processes, not only to protect the environment and the operator's personal health, but also to reduce the process, eliminating expensive secondary processing costs, greatly reducing production costs at the same time, save energy and materials.

02

Traditional craft

The traditional approach is to use a die temperature machine to heat the mold, but the shortcomings of this method are as follows:
① can not meet the needs of rapid heating and rapid cooling in high light injection molding;
②The temperature rise is small, and the welding marks on the surface of the product can only be reduced but not eliminated;
③The higher the hardness of plastic, the worse the fluidity. Therefore, the hardness of the surface of the products using this process can only reach HB level, which can not meet the actual use needs;
④ The mold expands when heating up, and shrinks when cooling down, making the clamping force very unstable. It is easy to cause various defects such as unsatisfactory beating, burning, and large internal stress.

03

High light injection molding technology

The steam highlight injection molding technology developed on the basis of the traditional process has been improved in response to the above defects:
① This technology opens the water pipe in the mold, and the steam is passed when it needs to be heated, and the cold water is passed when it needs to be cooled. After cooling, the residual water is blown out with compressed air to ensure that rapid heating and cooling can be achieved.
②To eliminate the faults of various products such as welding mark clamp and water mark lack of glue to the greatest extent;
③ Due to the large temperature rise, the surface hardness of the product is greatly improved by using plastics with H or even 2H hardness levels;
④Because when the pipeline is opened inside the mold, only the internal surface of the mold is heated or cooled, the overall expansion of the mold is small, so the various product defects caused by the instability of the mold locking force are reduced.

To produce high-quality high-gloss products, it is necessary to cooperate with injection molding machines, molds, temperature control equipment, special plastics for high-gloss products, boilers, cooling devices, etc.

Configuration of the plastic machine
① The rigidity of the clamping mechanism is better; Because the whole production process to keep heating and cooling. Therefore, the clamping mechanism of the injection molding machine must be rigid and strong to ensure the accuracy and stability of the clamping force. So as to ensure the surface quality of products.
② Selection of large mold locking injection molding machine: When using this process, because gas auxiliary injection can no longer be used, the clamping force required for the production of products will be relatively large.
③ Choose a smaller amount of injection according to the situation: such as the production of flat panel TV, LCD screen frame and other products, do not need a larger amount of injection glue, in the selection of injection molding machine as far as possible to choose a small amount of injection molding machine. The actual weight of the product is between 30% and 80% of the theoretical injection molding machine. If the amount of glue is too large, the glue material stays in the cylinder for a long time and is easy to decompose respectively, and the surface of the product will produce defects such as silver wire.
④ Equipped with special screws to produce high-gloss products used in the plastic hardness is high, the melting index is relatively low, because this requires the screw plasticization is better. At the same time, the shear of the screw can not be too large, otherwise the rubber material will be easy to decompose.

Mold arrangement

① The inner surface of the mold requires a very high finish to ensure the surface quality of the product;
② The pipeline inside the mold must be reasonable to ensure that it can quickly heat up and cool down;
③ The pipe inside the mold should have good thermal conductivity;
④ Because the production process needs to keep heating and cooling, the steel selected by the mold is better;
In the process of use, we should pay special attention to the maintenance of the mold to ensure dry and dust-free.

Configuration of temperature control equipment
① Temperature control should be very accurate, which is an important guarantee of product quality;
② The reaction of the temperature control equipment should be very fast to ensure high production efficiency.

Special plastics

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. However, the higher the hardness, the lower the melting index. The fluidity will be poor, so the appropriate plastic can be selected according to the production needs.

With the increasingly widespread application of plastic parts, as well as people's awareness of environmental protection and safety, steam seamless highlight injection molding has gradually become the forefront and popular technology in the future injection molding field.