What is the working principle of hot runner mold?

What is the working principle of hot runner mold?

Hot runner mold is an advanced mold design whose working principle mainly relies on precise temperature control and continuous flow of molten plastic.

The following are five aspects to explain the working principle of hot runner mold in detail:

1. Heating system

The core of the hot runner mold is the heating system, which is usually composed of an electric heating ring, a heating element and a temperature controller. The electric heating coil or heating element is embedded in the hot runner plate or diverter plate to provide uniform heat to the plastic, ensuring that the plastic always remains molten in the runner. The temperature controller is responsible for monitoring and regulating the temperature of the heating system to ensure that the plastic temperature is stable during the injection process.

2, the flow of molten plastic

During the injection process, the plastic particles enter the heating cylinder through the hopper of the injection molding machine and move forward under the push of the screw. As the plastic particles continue to advance inside the heating cylinder, they are gradually heated to a molten state. The molten plastic then flows into the mold cavity through a hot runner system.

3, injection and molding

After the molten plastic has filled the mold cavity, the injection molding machine applies pressure to ensure that the plastic is fully filled in each corner of the mold. The mold is then cooled to allow the molten plastic to solidify and form. Once the product has cooled enough, the mold opens and the ejector mechanism ejects the molded product from the mold.

4, continuous injection and temperature control

Unlike traditional cold runner molds, hot runner molds can keep the plastic in the runner in a molten state at all times, thus achieving continuous injection. This greatly reduces the waste of the material head and improves the production efficiency. At the same time, because the plastic always maintains a molten state in the flow channel, the molding cycle of the product is also shortened.

5. Heat balance and quality control

Another important feature of the hot runner mold is its heat balance. Through precise temperature control, it is possible to ensure that the temperature fluctuation of the molten plastic in the flow path is very small, thus ensuring the dimensional accuracy and quality stability of the product.

6. Summary

The working principle of the hot runner mold mainly depends on the heating system and the continuous flow of molten plastic. Through precise temperature control and injection process, hot runner molds enable efficient and high-quality product production. At the same time, the characteristics of continuous injection and reduced head waste also reduce the production cost.