The hottest highlight injection molding technology

Highlight injection molding technology: help 3C mold without melting marks

highlight injection molding technology can well produce shell products without melting marks, flow marks, streamlines, shrinkage marks and high gloss on the surface, which is particularly important for 3C mold industries such as flat panel TVs and computer LCD monitors

the process principle of high gloss injection molding is: heat the mold before and during mold closing, and inject when the temperature reaches the set conditions after mold closing. During the injection process, the mold continues to maintain high temperature, so that the rubber can maintain good fluidity in the mold during injection. After the injection is completed, when the pressure is maintained and cooled, the mold can be cooled by pressing 43r/min6 and pressing the start key, which can greatly shorten the cooling time of the product and improve the production efficiency

steam traceless high gloss injection molding technology is still an advanced production process in China. Because this technology greatly improves the surface quality and surface strength of products, and can cancel the subsequent spraying or painting processes, it not only protects the environment and the personal health of operators, but also saves expensive secondary processing costs due to the reduction of process flow, and saves energy and materials while greatly reducing production costs

the traditional method is to use the mold temperature machine to heat the mold, but the shortcomings of this method are as follows:

1) it can not meet the needs of rapid temperature rise and rapid temperature drop in high gloss injection molding

2) the range of temperature rise is small, and the weld line on the surface of the product can only be reduced but cannot be eliminated

3) the higher the hardness of plastic, the worse the fluidity. Therefore, the surface hardness of products with this process can only reach Hb level, which cannot meet the actual use needs

4) when the mold is heated up, it will expand, and when it is cooled down, it will shrink, making the clamping force very unstable. It is easy to cause various defects such as dissatisfaction, charring, large internal stress and so on

and the steam high gloss injection molding technology developed on the basis of this process has been improved against the above defects:

1) this technology opens the water pipe in the mold, and when it needs to raise the temperature, pass the steam, and when it needs to lower the temperature, pass the cold water, and after cooling, blow out the residual water with compressed air to ensure rapid temperature rise and drop

2) to eliminate various product faults such as weld line clamp and water mark lack of glue to the greatest extent

3) due to the large temperature rise, the surface hardness of products is greatly improved by using plastics with H or even 2H hardness level

4) when opening pipes inside the mold, only the inner surface of the mold is heated or cooled, and the overall expansion of the mold is small, so various product defects caused by the instability of the clamping force are reduced

in order to produce high-quality high gloss products whose standard experimental method requires that the calculation should become the zigzag stress at 5%, injection molding machines, molds, temperature control equipment, special plastics for high gloss products, as well as boilers, cooling devices and other aspects need to be coordinated

1. The configuration of the plastic machine

1) the rigidity of the clamping mechanism is better; Because the whole production process keeps heating up and cooling down. 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) choose the injection molding machine with large mold locking: when using this process, because gas assisted injection can no longer be used, the mold locking force required for the production of products will be relatively large

3) choose a small injection quantity according to the situation: for example, when producing flat-panel TVs, LCD frames and other products, it is not necessary to have a large injection quantity. When choosing an injection molding machine, try to choose an injection molding machine with a small injection quantity. The actual weight of the product is best between 30% - 80% of the theoretical injection amount of the injection molding machine. If the glue injection amount of the machine is too large, the glue will stay in the barrel for a long time, and it is easy to decompose separately, and defects such as silver wire will appear on the surface of the product

4) the plastic used to produce high gloss products with special screw has high hardness and relatively low melt index, so it is required that the screw plasticization is better. At the same time, the shear of the screw should not be too large, otherwise the rubber will be easy to decompose

2. Mold configuration

1) the inner surface of the mold requires a very high finish to ensure the surface quality of the products

2) the pipes inside the mold must be reasonable to ensure rapid temperature rise and drop

3) the pipes inside the mold should have good thermal conductivity

4) as the production process requires constant heating and cooling, the steel used for the mold is better

5) pay special attention to the maintenance of the mold during use to ensure that it is dry and dust-free. Meet the increasingly stringent requirements of exhaust emission regulations

3 Configuration of temperature control equipment

1) temperature control should be very accurate, which is an important guarantee for product quality

2) the reaction of temperature control equipment should be very fast to ensure high production efficiency

4. Special plastics

when producing products with high surface quality, the commonly used plastics are ABS, pc+abs or pmma+abs. Among them, the hardness of ABS is the lowest, and the hardness of pmma+abs is the highest, up to h, or even 2H. However, the higher the hardness is, the lower the melt index is. The fluidity will become poor, so appropriate plastics can be selected according to production needs. With the increasingly wide application of plastic parts in liquid level switch stores, and people's awareness of environmental protection and safety is gradually increasing, steam traceless high gloss injection molding has gradually become the cutting-edge and popular technology in the field of injection molding in the future