What is hot runner system

Money, speed, and precision – 3 things that you want for your business if at all possible. These are hard to come by together – none of these companies will try to tell you otherwise. However, hot runner systems for medical injection molding are the best way to get these three big aspects of running a company together with one piece of equipment.

What is Hot Runner System?

Hot runner is a plastic component that serves as a pathway for the molten polymer to flow from the extruder into the automotive injection mould  cavity. It also acts as a mechanical support for the polymer as it solidifies, ensuring dimensional accuracy and surface quality.

Hot Runner is a device that is for transfering heat and pressure to the automotive injection cavity. It consists of a hot runner manifold, nozzle and runner pins/sprue bushing. The hot runner manifold provides a distribution of flow to the nozzles and sprue bushings. The nozzles deliver molten plastic into the mold cavity. The sprue bushings connect to runners.This provides channels for plastic to flow from the sprue gate into the mold cavity.

The hot runner assembly connect to the extruder head . A large pipe which runs through the entire length of the machine frame. This pipe carries molten plastic from the extruder head down through the Hot Runner Assembly and into each individual nozzle.

There are two main types of Hot Runner systems:

-Direct: The molten material flows directly through an opening in the automotive injection mould cavity wall (or mold), usually created by machining or milling

-Indirect: The molten material flows through one or more channels in a separate piece of hardware called “runner system”.

What are the advantages of a hot runner system?

The benefits of using a hot runner system include:

Increased productivity – The use of hot runners can increase productivity by up to 30 percent compared with standard injection molding techniques. Greater efficiency means that more parts can be ready in less time and at lower cost per part.

Reduced labor costs – The elimination of manual work makes it possible for one operator to run multiple molds simultaneously, which reduces labor costs associated with manual handling of raw materials. This works especially well with large parts where there is little room for human error or misalignment between the two halves of the mold during assembly or disassembly processes.

Improved quality control – With hot runners, it is easier to maintain consistent material flow through the automotive injection mould because there are fewer places where air can become trapped and impede flow through the channels inside the tool. The temperature of the material is more consistent, which leads to a smoother surface finish and improved tolerance for dimensional accuracy.

Hot runner systems are used in the following industries

Automotive industry – automotive manufacturers use hot runners to produce interior parts such as dashboards, armrests and seat backs. These hot runners manufacture these parts at high speeds while maintaining accuracy and quality control. The hot runner can also make small exterior parts such as mirrors and door handles.

Electronics industry – the electronics industry produces circuit boards using hot runners. These circuit boards are assembled on a large scale using automated machinery that requires very precise temperature control during production. A hot runner system allows for accurate temperature control during assembly . It ensures that all components adhere properly and work as intended once installed in a final product.

Medical devices industry – medical device manufacturers use hot runners for their manufacturing process because it allows them to mass produce high quality parts in high quantities quickly and efficiently without sacrificing quality or accuracy due to manual labor errors which can occur when using traditional injection molding methods which require human intervention throughout the entire process.


Hot Runner Systems can reduce cycle times and eliminate the need to first machine parts, therefore improving productivity and profitability. They are primarily for cavity and core inserts in injection molding, but also for other processes such as blow molding. Hot Runner systems eliminate the need to machine cavities and cores before or after molding components. The system consists of a hot runner tool. This tool install into a standard injection molding machine and replace with a specially-designed core. When using a hot runner system, there are no extra steps needed to machine parts because they are in place by the cavity insert. Hot runner systems also allow for faster changeover times between products. They can help in situations where two different parts must be produced side-by-side on the same machine.

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