How to control the optimal injection temperature during injection molding
Injection molding is an engineering technology, which involves transforming plastics into useful products that can adhere to their original functions. The important process conditions of injection molding are the temperature, pressure and corresponding action time that affect the plasticizing activity and cooling.
Barrel temperature: the temperature required to be controlled in the injection molding process includes barrel temperature, nozzle temperature and mold temperature. The first two temperatures mainly affect the plasticization and activity of plastics, and the other is mainly affecting the activity and cooling of plastics. Each kind of plastic has different active temperature. For the same plastic, due to different sources or brands, its active temperature and decomposition temperature are different, which is due to different average molecular weight and molecular weight distribution. The plasticization process of plastics in different types of injection machines is also different, so the barrel temperature is also different.
Nozzle temperature: the nozzle temperature is usually slightly lower than the minimum temperature of the barrel, which is to avoid the “salivation” of molten material in the straight through nozzle. The temperature of the nozzle shall not be too low, otherwise the nozzle will be blocked due to the early setting of the melt, or the function of the product will be affected due to the injection of the early setting material into the mold cavity.
Mold temperature: mold temperature has a great impact on the internal function and apparent quality of products. The mold temperature depends on the crystallinity of the plastic, the size and structure of the product, functional requirements, and other process conditions (melt temperature, injection speed, injection pressure, molding cycle, etc.)
