how to get a high gloss surface in injection molding
how to get a high gloss surface in injection molding
Process of high gloss injection molding:
Warm the mold before and during mold closing. After mold closing, inject when the temperature reaches the set conditions. During the injection process, the mold continues to maintain high temperature, which can maintain good fluidity in the mold during rubber injection. When the injection is completed and the pressure is maintained for cooling, the mold is cooled, which can greatly shorten the cooling time of the product and improve the production efficiency.To produce high-quality high gloss products, injection molding machines, molds, temperature control equipment, special plastics for high gloss products, boilers, cooling devices and other aspects need to be coordinated:
1. Configuration of plastic machine
① The rigidity of the clamping mechanism is better; Due to the continuous heating and cooling in the whole production process. Therefore, the mold locking mechanism of the injection molding machine must be rigid and have good strength to ensure the accuracy and stability of the mold locking 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 smaller injection quantity according to the situation: for example, when producing flat-panel TVs, LCD frames and other products, there is no need for a larger injection quantity. When selecting an injection molding machine, try to choose an injection molding machine with a smaller injection quantity. The actual weight of the product is the best between 30% ~ 80% of the theoretical glue 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, resulting in defects such as silver wire on the surface of the product.
④ Equipped with special screw to produce high gloss products, the plastic used 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 pipeline inside the mold must be reasonable to ensure rapid temperature rise and drop;
③ The pipe inside the mold should have good thermal conductivity;
④ As the production process needs constant heating and cooling, the steel used for the mold is better;
⑤ In the process of use, we should pay special attention to the maintenance of the mold to ensure that it is dry and dust-free.
3. Configuration of temperature control equipment
① Temperature control should be very accurate, which is an important guarantee of product quality;
② The reaction of temperature control equipment should be very fast to ensure high production efficiency.
4. Special plastic
When producing products with high surface quality, commonly used plastics include ABS, PC + ABS or PMMA + ABS. The hardness of ABS is the highest, even PMH + 2mA. However, the higher the hardness, the lower the melt index. The fluidity will be poor, so appropriate plastics can be selected according to production needs.
Steam traceless high gloss injection molding technology greatly improves the surface quality and surface strength of products, and can cancel the subsequent spraying or painting processes, which 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, greatly reduces the production cost and saves energy and materials.
