The injection pressure loss in the hot runner system cannot be ignored. Many hot runner mold customers have a misconception that the plastic solution located in the hot runner is always hot, so the injection pressure loss of the hot runner is much smaller than that of the cold runner.

In fact, in order to meet the needs of hot runner structure design, the flow distance of the melt in the hot runner system will greatly increase, so the injection pressure loss in the hot runner system cannot be underestimated. In practical applications, there are many situations where injection molding is difficult due to excessive pressure loss in the hot runner system. Therefore, CAE software should be used for channel analysis and calculation of plastics with poor processing flowability (such as PC, POM, etc.), solutions with large flow distances in the hot runner system, and products with large weight.

After the production of the hot runner injection mold is completed, the shutdown steps similar to the injection machine must also be followed:

1、 Turn off the heater of the hot runner system.

2、 Turn off the cooling system of the mold again. For the heated hot runner system, the cooling system of the mold can only be turned off after the temperature drops to 80 ℃.

Before ending the production of the hot runner injection mold, it is necessary to perform material replacement and cleaning for high-temperature plastics and thermosensitive plastics. For some plastics such as PC, they can stay in the hot runner system and the material barrel of the injection machine. At a low temperature of about 160 ℃, the injection can be interrupted for up to 12 hours, but it cannot be interrupted for a long time. Thermosensitive plastics cannot interrupt injection. In the injection machine barrel and the hot runner, there is a strong adhesion between the cured or semi cured plastic and the metal surface, even causing the nitride layer to separate. The screw of the injection machine and the pin of the switch nozzle have a surface nitride layer. Therefore, do not interrupt the injection and perform melt cleaning before shutting down.