Injection molding is an engineering technology, and what it touches is to transform plastics into useful products that can maintain their original functions. The important process conditions of injection molding are the temperature, pressure and the corresponding working time that affect the plasticizing activity and cooling.
1. Barrel temperature: The temperature that needs to be controlled during the injection molding process includes barrel temperature, nozzle temperature and mold temperature. The first two temperatures mainly affect the plasticization and activity of the plastic, and the second temperature affects the activity and cooling of the plastic. Each kind of plastic has different activity temperature. The same kind of plastic has different activity temperature and decomposition temperature due to different sources or grades. This is due to the difference in average molecular weight and molecular weight distribution. Plastics are injected in different types. The plasticization process in the machine is also different, so the temperature of the barrel is not the opposite.
2. Nozzle temperature: The nozzle temperature is usually slightly lower than the lowest temperature of the barrel, this is to avoid the "salivation" that the melt can occur in the straight-through nozzle. The temperature of the nozzle should not be too low, otherwise it will cause premature solidification of the melt and block the nozzle. Perhaps the function of the product will be affected due to the injection of the premature solidification material into the cavity.
3. Mold temperature: Mold temperature has a great influence on the internal function and apparent quality of the product. 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 and injection pressure, molding cycle, etc.).