In our last talk, we covered the basics of injection molding. Now, let’s dig a bit deeper into the world of injection molding, focusing on something called hot runner systems. These systems have become really popular because they offer some cool advantages over the usual cold runner systems. In this article, we’re going to break down what is hot runner system in injection mold design systems, the different types, and the pros and cons of using this type of injection molding.

（The picture comes from the moldmasters.com website. If there is any infringement, please contact us to delete it）

What Is A Hot Runner System?

A hot runner mold system is like a smart injection molding setup with two plates. Instead of using a separate channel for the melted plastic, it has a fancy heated system that manages everything. Imagine a super-controlled heating system with pipes and nozzles that keep the plastic in a melted state until it’s ready to be injected into the mold. This happens through carefully controlled gates or drops. Once inside the mold, the plastic cools down, shapes up, and then gets pushed out of the mold. The picture below shows how this whole process works in a hot runner system.

Internet picture,for reference only

When The Hot Runner System Is Needed?

In injection molding, the consideration of hot runner systems is paramount in various scenarios, where their unique advantages make them an excellent choice for optimizing the manufacturing process. Let’s delve into specific application examples highlighting when and why hot runner systems prove indispensable:

Reducing Material Waste:

Scenario: You’re producing intricate, small-sized components with a conventional cold runner system, leading to a significant amount of wasted material in the form of cold runners.

Solution: Hot runner systems excel in such cases by maintaining a molten state within the runners, eliminating the need for cold runners, and drastically reducing material waste.

Enhancing Cycle Time:

Scenario: Your production line demands swift turnarounds, but conventional molding cycles are causing delays.

Solution: Hot runner systems accelerate the injection process by ensuring a constant molten state, resulting in shorter cycle times and increased production efficiency.

Improving Part Quality:

Scenario: You’re dealing with complex designs or delicate parts, and the current molding process yields inconsistent results.

Solution: Hot runner systems offer precise control over each gate, preventing gate vestiges and ensuring uniform mold cavity filling, thereby enhancing the quality of intricate and delicate parts.

Streamlining Complex Molds:

Scenario: Your mold involves multiple cavities or intricate geometries, leading to uneven filling and defects.

Solution: Hot runner systems provide tailored control over each gate, facilitating uniform filling in complex molds and reducing the likelihood of defects.

Material Compatibility:

Scenario: You’re working with heat-sensitive or high-performance materials that are prone to premature solidification.

Solution: Hot runner systems maintain optimal processing conditions for such materials, preventing premature solidification and ensuring consistent part quality.

Cost-Effectiveness for Large Production Runs:

Scenario: You’re considering the initial investment for hot runner systems but are uncertain about the long-term benefits.

Solution: While setup costs may be higher, hot runner systems prove cost-effective over large production runs due to reduced cycle times and material waste.

What Are The Different Types of Hot Runner Molding Systems?

Open Sprue Systems:

Description: Open sprue systems operate like a direct pipeline. The molten plastic flows openly from the injection unit into the mold cavities without any intermediary channel.

Application: Best suited for simple molds where the focus is on ease of maintenance and uncomplicated design.

Valve Gate Systems:

Description: Valve gate systems employ a mechanical valve at the gate to control the flow of molten plastic. This precise control minimizes drooling and ensures a clean break-off.

Application: Ideal for applications requiring precision, such as molding complex parts with specific gating requirements.

Sequential Valve Gate Systems:

Description: In sequential valve gate systems, multiple gates open in a sequential manner, allowing for a controlled and sequential fill of the mold cavities. This helps to reduce internal stress and improve part quality.

Application: Effective for large, complex parts with varying thicknesses, where sequential filling can mitigate defects.

Hot Sprue Systems:

Description: Hot sprue systems maintain the plastic in a molten state within the sprue, eliminating the need for cold slugs. This helps in reducing material waste and enhancing the overall efficiency of the molding process.

Application: Suitable for molds with longer runners, minimizing material waste and ensuring a consistent flow of molten plastic.

Insulated Runner Systems:

Description: Insulated runner systems feature channels that are thermally insulated to reduce heat loss. This insulation promotes consistent material flow and helps maintain a stable temperature within the runner system.

Application: Ideal for molding heat-sensitive materials and scenarios where maintaining precise temperature control is critical for part quality.

Manifold Systems:

Description: Manifold systems distribute molten plastic through a network of channels, ensuring the even filling of multiple mold cavities simultaneously. This promotes uniform part quality.

Application: Well-suited for molds with numerous cavities or intricate designs, providing precise control over the distribution of molten plastic.

In-Mold Rheology Control Systems:

Description: In-mold rheology control systems leverage advanced technology to monitor and control the flow and viscosity of molten plastic in real-time. This ensures optimal processing conditions.

Application: Effective for optimizing the molding process with materials that exhibit varying rheological properties, offering enhanced control and consistency.

Understanding these different types of hot runner molding systems allows manufacturers to make informed decisions based on the specific requirements of their molding projects, contributing to improved efficiency and the production of high-quality plastic components.

What are The Different Heating Methods Within Hot Runner Systems?

Internally Heated:

Internally heated runner systems excel in flow control, utilizing torpedo cartridge heaters with embedded thermocouples inside the runners. This unique internal heating approach significantly reduces heater loads compared to externally heated hot runner manifolds, enhancing overall efficiency. Internally heated molds are the preferred choice when heightened flow control is imperative.

Externally Heated:

Externally heated manifolds employ a range of temperature control systems, such as cartridge heaters, cast-in heaters, heat pipes, heater bands, coil heaters, and torpedo heaters. This configuration proves especially effective for polymers sensitive to thermal variations, guaranteeing optimal heat transfer and expediting the startup process.

Insulated Runners:

Insulated hot runner molding systems incorporate enlarged channels within the mold plate, effectively utilizing the heat insulation properties of molten thermoplastic. This innovative design facilitates the formation of thick layers of thermally insulating material around the exterior of the insulated runner, enabling the molten thermoplastic to flow through the central core. While these insulated runners offer a simpler design and cost advantages compared to internally and externally heated systems, challenges may arise concerning uneven filling. This system excels when working with heat-sensitive thermoplastic polymers and becomes particularly advantageous in scenarios requiring frequent color changes.

Any Disadvantages of Hot Runner Molds?

While hot runner systems offer remarkable advantages, certain drawbacks should be considered:

Higher Costs (Mold and Maintenance):

Complex mold features and intricate maintenance requirements contribute to a higher price tag. Additionally, constant heating needs lead to increased energy consumption.

Complex Maintenance & Operation Requirements:

Stemming from the complexity of additional hot runner components, internal/external heating may result in additional wear and tear on molding machines.

Polymer Thermal Sensitivity:

Some thermally sensitive materials may not be suitable for hot runner systems.

Color Changes Challenges:

Changing colors involves a multi-step purge, leading to significant scrap (especially for large parts) and hours of machine downtime.

Applications of Hot Runner Molding

Automotive Component Manufacturing:

A leading automotive manufacturer adopts hot runner molding for producing intricate plastic components, such as dashboard panels and interior trim pieces. Hot runner systems enable precise control over the injection process, ensuring uniform filling of complex molds. This results in high-quality, visually appealing components with reduced cycle times, contributing to overall production efficiency.

Medical Device Manufacturing:

A medical device company incorporates hot runner technology for molding intricate parts used in diagnostic equipment and disposable medical devices. The precision offered by hot runner systems is crucial in the production of intricate medical components. Reduced material waste and enhanced part quality contribute to meeting stringent industry standards while maintaining cost-effectiveness.

Consumer Electronics Manufacturing:

A consumer electronics manufacturer adopts hot runner molding for producing sleek and precisely shaped casings for smartphones and other electronic devices. Hot runner systems contribute to the flawless appearance of electronic casings by eliminating gate vestiges and ensuring consistent filling. The reduction in material waste aligns with sustainability goals, making it an environmentally conscious choice.

Packaging Industry Manufacturing :

A packaging company utilizes hot runner systems to mold intricate and customized designs for packaging containers. Hot runner technology enables the production of complex and aesthetically pleasing packaging solutions. The ability to control the flow of molten plastic ensures uniform wall thickness, contributing to the structural integrity of the packaging.

Injection Molding for Toys part Manufacturing：

A toy manufacturing company employs hot runner systems to produce intricate and detailed plastic parts for toys. The use of hot runner systems allows for efficient production of complex toy components with reduced cycle times. This ensures a faster time-to-market for new toy designs, meeting the demands of a dynamic industry.

In each of these examples, hot runner molding systems have proven instrumental in meeting the specific needs of diverse industries. The advantages include precision molding, reduced material waste, enhanced part quality, and overall cost-effectiveness. As technology continues to advance, the applications of hot runner systems are expected to expand further, influencing the landscape of plastic injection molding across various sectors.

Hot runners VS Cold runners

Hot Runners Bring Optimization

Alternative melt-delivering systems include hot runners. The function is similar to the cold runner, providing a route for liquid resins to flow through the system using highly technical and meticulous designs. Generally speaking, a hot runner cannot allow liquid resin to solidify. It is completely wrapped around insulated steel tanks without being exposed to air. This manifold passes resin through tubes that provide entry to the entrance and the cavity. The cylinders can also be controlled through thermocouples and heat exchangers to keep melted molten plastics warm.

Cold Runner Limitations

In injection molding, a crucial requirement in the molding process is delivering the melt through the barrels of the chamber. Melt delivery managers will impact primarily upon final quality. The controlled operation of resin flows, pressure, and heat is critical. The successful manufacturing process is closely linked to the design of the melting system so an examination of cold runners is useful. Cold runners solidify plastic flow channels in molds and are removed after molding.

Conclusion:

Hot runner systems stand as the optimal and cost-effective choice for medium to high-volume production runs, ensuring consistent and repeatable results. However, if your project demands prototyping or testing various color options, cold runner systems may prove effective. Stay tuned by subscribing to receive notifications for our upcoming content, where we will delve into cold runner molding basics and help you determine the perfect system for your next project.

Well-known Hot Runner Brands:

1. Well-known North American Hot Runner Brands:

   – MOLD-MASTERS (Master) – Canadian brand, holds the highest market share worldwide

   – DMEINCOE – American brand, a pioneer in North American standards

   – HUSKY (Husky) – Canadian brand

   – CACO – American brand

   – FASTHEAT – American brand

   – HASCO – German brand

2. Renowned European Hot Runner Brands:

   – SYNVENTIVE – Dutch brand

   – EWIKON – German brand

   – GUNTHERMASTIP – German brand specializing in hot runners for bottle preform molds

   – SPEAR – German brand

   – PLASTHING – British brand

   – UNITEMP – Swedish brand

   – THERMOPLY – Italian brand

3. Well-known Asian Hot Runner Brands:

   – FISA – Japanese brand, the world’s first spring self-locking needle valve hot runner company

   – HOTSYS – South Korean brand

   – YUDO – Holds a leading market share in Asia

   – SINO (Xianrui) – China (YUDO subsidiary)

   – MOULD-TIP – Shenzhen, China

   – ANNTONG (yingtong) – Taiwan, China

   – KLN (Klonning) – Shanghai, China

   – ANOLE – ANOLE

   – NISSEN-TIP – Ningsu

   – MOZOI – Spring self-locking needle valve

4. Renowned Australian Hot Runner Brand:

   – MASTIP – New Zealand brand

点评：

Brief description of hot runner usage in the moldmkaing industry：

DME (North American Standard) is one of the world’s largest suppliers of mold standard parts, with fifty years of experience and a long history. Many of our USA customers like to use, but cost little more expensive than YUDO.

The biggest feature of HUSKYFISA (the first spring self-locking needle valve) is that it relies on the balance of spring and injection pressure to control the needle valve switch. It is easy to assemble, debug and maintain. The mold accuracy is not high. Japanese domestic customers basically have the ability to maintain themselves. It is widely used in In home appliances, automotive trim parts, and precision multi-cavity molds.

GUNTHERMASTIP (specializing in hot runner for preform molds)

MOLD-MASTER (the world’s highest share), among which MOLD-MASTER can be called the Rolls-Royce of hot runner – the heating part is on the nozzle. A large part of their cost is in debugging and maintenance, and customers basically cannot maintain it themselves.

YUDO (leading market share in Asia), the use of foreign hot runners in molds has reached 80 to 90%, while the use of YUDO hot runners in domestic molds is about 30%.

The above is just a rough reference. With the market development of different companies, the market share may change.

But despite this, as people’s living standards improve and their requirements for product use become higher and higher, the use of mold hot runners will become more and more common. The popularity and popularity of hot runner molds is also to improve the utilization rate of raw materials and product quality. When designing molds, it is implemented together with hot runner design. This will definitely bring benefits to the enterprise. Therefore, when customers develop projects, they open molds in the early stage. Investing in a hot runner may seem like a lot of money, but as long as it is mass-produced, it actually saves customers the unit cost of production and products.

#Sino-MoldIndustrial

#sinomold

#Injectionmold

#cncmachining

#hotrunner

#plasticmold

#moldfactory

More topic you would like to know?

Do I need to find my hot runner system supplier?

The hot runner injection mold system？

Hot runner vs cold runner injection molding systems？

Is There Too Much Waste During the Hot Runner Injection Molding Process?

Why Use Hot Runner Injection Molding Instead of a Cold Runner Injection Molding System?

What Are the Different Types of Hot Runner Systems?

what is hot runner system in injection mold design?