Hot runner system and injection molding problems and solutions

In hot runner systems, injection molding pressure loss is a critical factor that cannot be ignored. Many users of hot runner molds often fall into a misconception: they believe that since the injection melt within the hot runner system remains at a high temperature, the injection molding pressure loss in hot runners will be significantly lower compared to cold runners.

However, to accommodate the complexity of hot runner structural designs, the flow distance of the melt within the hot runner system often increases significantly, resulting in injection molding pressure losses in hot runner systems that are equally noteworthy. In practical production applications, injection molding challenges caused by excessive injection molding pressure loss in hot runner systems are not uncommon. Therefore, when dealing with complex situations such as processing plastics with poor flowability, long melt flow distances within the hot runner system, and heavy molded parts, we should fully utilize CAE software for runner analysis to ensure the smooth progress of the production process.

After the hot runner injection molding production is completed, the shutdown procedure of the injection molding machine is also crucial and should be followed in the following sequence:

Firstly, turn off the heaters of the hot runner system to ensure that the system gradually cools to a safe state.
Subsequently, turn off the cooling system of the mold to prevent damage caused by sudden temperature changes.

Furthermore, the injection molding machine has a significant impact on the performance of hot runner molds, specifically manifested in the following aspects:

The injection molding machine must have the capability to accurately place inserts, labels, or flakes into the mold.
The injection molding machine should effectively eject plastic parts or accelerate their ejection process to improve production efficiency.
By controlling plastic movement and reducing startup time accessories, the injection molding machine can further optimize the production process.
Before starting the injection molding machine, the mold should be preheated to ensure that the melt can smoothly fill the mold.
The injection molding machine should also have the ability to quickly change molds, reducing the connection time for cooling water pipes, air circuits, electrical circuits, and hot runner temperature control boxes, thereby improving production efficiency.

During the use of hot runners, if adhesive problems are encountered, the following analysis is required:

For old molds, adhesive problems may be caused by damaged heating tubes in the hot runner. In this case, electrical workers should be promptly contacted for inspection and repair.

For new molds, check the mold's verticality, the installation of the hot runner, and whether the gate has been deformed due to nozzle impact. If these aspects are normal, the problem may be caused by an internally too-small water inlet size and excessive injection pressure. In such cases, adjustments to the mold are needed to reduce the injection pressure and prevent the occurrence of adhesive problems.