Core Tip: The hot runner is heated to ensure that the plastics in the runners and gates remain molten. Since the heating rod and the heating coil are arranged near or in the center of the flow path, from the nozzle exit of the injection molding machine to the gate

     The hot runner is heated to ensure that the plastics of the runners and gates remain molten. Since the heating rod and the heating ring are arranged near or in the center of the flow path, the entire flow path from the nozzle exit of the injection molding machine to the gate is in a high temperature state, so that the plastic in the flow path is kept molten, and it is generally unnecessary to open the flow path to take out the condensation after the shutdown. Material, just turn on the flow channel to the required temperature. Therefore, hot runner processes are sometimes referred to as hot manifold systems, or as no runner molding.

With the increasing application of hot runner technology, the proportion of hot runner molds in plastic molds will gradually increase. In foreign countries, more than 50% of the molds produced by many plastic mold factories use hot runner technology, and some even reach more than 80%. The effect is very obvious. Hot runners have also been used in production in China, but the current total is less than 10%. This gap is quite large, but it also means that the industry has considerable room for development in China.

In recent years, the gradual promotion of hot runner technology in China is largely due to the rapid export of domestic molds to European and American companies. In Europe and the United States, injection molding production has relied heavily on hot runner technology. It can be said that molds that do not use hot runner technology are now difficult to export. However, due to the high price of many imported hot runner molds, a large number of domestic manufacturers can not accept, so there are some domestic commercial hot runner molds. This has great benefits for the promotion of hot runner technology in China.

At the same time that hot runner technology is gradually getting hot in China, its components show several major development trends.

The first is component standardization. At present, users require mold design and manufacturing cycle to be shorter and shorter, standardizing hot runner components, not only help to reduce the duplication of design work and reduce mold cost, but also facilitate the replacement and repair of vulnerable parts. The nozzles, stems and manifolds of companies such as Husky, Presto and MoldMaters are standard and easy to change and deliver quickly. Now it takes only four weeks to deliver the mold abroad.

The second is the miniaturization of components. The miniaturization of components enables multi-cavity and multi-cavity filling of small products. By reducing the nozzle space, more cavities can be placed on the mold, increasing product yield and injector utilization, which is important for the modern plastics processing industry where 'time is money'. MoldMaters, an internationally renowned mold company, has developed nozzles for small parts, including integral heaters, needle tips and melt channels. The volume is less than 9 mm, the gate distance is only 10 mm, and the product can be molded to a mass of 1 to 30 grams.

The third is reliable design. Nowadays, major mold companies at home and abroad attach great importance to the design of hot runner plates and the development of pressure distribution, temperature distribution and sealing of hot nozzle joints. The development and utilization of laminated hot runner injection molds is also a hot spot. The stacking mold can effectively increase the number of cavities, and the injection molding force requirement of the injection machine only needs to increase by 10% to 15%. Stacked hot runner molds have been industrialized in some developed countries abroad.

The fourth is the accuracy of the temperature control system. In hot runner mold molding, the development of more precise temperature control devices to control the temperature of the molten resin in the hot runner plate and gate is an effective measure to prevent overheating degradation of the resin and degradation of product performance.

It can be said that the wide application of hot runner technology is a major revolution in plastic molds. In terms of injection molding, it has quite a few unparalleled advantages. As technology matures and manufacturing costs decrease, hot runner technology will increasingly show significant advantages. In recent years, world-famous hot runner technology suppliers have entered the Chinese market in various ways, showing the huge development potential of China's hot runner mold market.

At the same time, this trend is also playing a huge role in promoting the rapid improvement of China's mold industry technology. A large number of emerging private enterprises in China also recognize the unlimited business opportunities in this field and have established hot runner production enterprises. This is of great significance for reducing the use cost of hot runner technology and speeding up the application. However, in general, most of the technologies that local enterprises in China can provide are still relatively primitive. The choice of space is small, the quality is unstable, and the maintenance period is short, which often affects the trust of downstream enterprises in their products. Therefore, the formulation of national standards for hot runner components, the active production of inexpensive and high-quality components, and the promotion of hot runner technology are the key to the development of domestic hot runner molds.