What is the key technology of hot runner application

A successful hot runner mold application project requires multiple links to be guaranteed. Among the most important are two technical factors: one is the control of plastic temperature, and the other is the control of plastic flow.


1. The control of plastic temperature is extremely important in the application of hot runner molds.

Many processing and product quality problems that occur in the production process directly stem from the poor temperature control of the hot runner system. Such as the problem of poor quality of product gates when using hot pin gate method for injection molding, problems with valve pin closing difficulty when molding with valve gate method, and inconsistent filling time and quality of parts in multi-cavity molds.

If possible, you should choose a hot runner system with separate temperature control in multiple areas to increase the flexibility and adaptability of use.

2. Control of plastic flow

Plastics must flow in balance in the hot runner system. The gates should be opened at the same time so that the plastic fills the cavities simultaneously. For parts with large differences in weight, the runner size design should be balanced. Otherwise, there will be problems such as insufficient filling and holding pressure for some parts, excessive filling and holding pressure for some parts, excessive flashing and poor quality. The size design of the hot runner should be reasonable.

The size is too small and the mold filling pressure loss is too large. If the size is too large, the volume of the hot runner is too large, and the plastic stays in the hot runner system for too long, which damages the material properties and causes the parts to fail to meet the requirements of use after molding.

A hot runner gating system can be understood as an extension of injection molding machinery. The function of the hot runner system is to deliver the thermoplastic melt to the vicinity of the forming mold or directly into the mold adiabatically.

The hot runner can be heated independently, but thermally insulated in the injection mold, so that it can individually compensate for the heat loss caused by contact with the "cold" mold. Hot runner molds have been successfully used to process various plastic materials. Almost all plastic materials that can be processed with cold runner molds can be processed with hot runner molds.