What is hot runner?

The so-called hot runner molding means that the plastic sent from the nozzle of the injection machine to the gate is always kept in a molten state, and does not need to be solidified as waste after each mold opening, and the melt accumulated in the casting system can be injected at the time of another injection of cavity.

The ideal injection molding system should form parts with the same density and not be affected by all the runners, flash and gate outlets. In contrast to cold runners, for hot runners to do this, they must maintain the molten state of the material in the hot runner and do not leave the molded part. Hot runner processes are sometimes referred as heat manifold systems, or as runnerless molding.

Generally speaking, the heat collecting manifold can be regarded as the extension of the nozzle of the cylinder and the injection molding machine. The function of the hot runner system is to deliver the material to every gate in the mold.

The principle of hot runner

The hot runner system consists of three parts: the heat nozzle, the runner plate and the temperature control box. It is a perfect structure for injection molding.

The working principle of the hot runner system is to install heaters in the plastic mold, and to keep the runner of the mold in molten state by using the principle of heating and temperature control. Just like the injection molding machine's battery directly extends to the injection point of the product cavity, making the product more direct and easy to shape. The advantages of the hot runner shorten the injection period, improve production efficiency and reduce costs.

There is no water outlet material, which can be fully automated and can also solve the problem of water recovery.

It can improve the consistency and balance of the product and the quality of the products. It can also improve the appearance of the gate, reduce injection pressure and clamping force.It makes the process of products easy.

Hot runner performance

Precise control of melt plastic temperature eliminates material degradation. Balanced runner design with even cavity filling. There is no dead zone in the flow path to ensure rapid color change and prevent degradation of the material to minimize pressure loss.

Composition of hot runner

The hot runner system consists of hot nozzles, hot runner plates, high-precision temperature controllers, etc. The same mold can be equipped with single or multiple nozzles (up to 148).

Hot runner selection

Many conditions are considered when choosing a hot mouth, such as different plastic characteristics, product shape, size, thickness, weight, cavity arrangement and gate location. We have several different shapes and sizes of hot mouths and hot runners board to suit a variety of products.