1. Higher temperature
Mold molding has higher temperature requirements (generally around 80°C-130°C). After the injection is transferred to pressure holding, cooling water is used to reduce the mold temperature to 60-70°C. Holding pressure molding at higher mold temperature is beneficial to eliminate defects such as weld lines, flow marks, and product internal stress. Therefore, the mold needs to be heated during work. In order to prevent heat loss, a heat shield is usually added to the fixed mold side.
2. The surface of the cavity is extremely bright (usually mirror level 2 or higher)
The products produced by the high-gloss mold can be directly used for installation (assembly) without any surface treatment. Therefore, it has high requirements for mold steel and plastic materials.
3. The hot runner system has more thermal nozzles
Each thermal nozzle must be equipped with a sealing needle and an independent air passage, which is individually controlled by solenoid valves and time relays to realize time-sharing glue feeding, so as to achieve the purpose of controlling or even eliminating weld marks. The control method is complicated.
4. Heating method
Mold heating methods usually have steam (hot water) heating and electric heating rod (tube) heating. The steam (hot water) heating method is to input steam (hot water) into the mold during the injection molding process through a specific temperature control machine, so that the mold quickly rises up; after injection molding, the mold is cooled with cold water to quickly cool the mold. The electric heating method is the same as the water heating temperature controller in principle, that is, the heat source is different. Electric heating is a secondary energy source, and water heating is a tertiary energy source. According to the principle, electric heating energy consumption is low, and the utilization rate is high. Good energy-saving benefits. It is easy to use, so it is said that if it is a flat (noodle) product, electric heating is still economical.