Hot runner molds are widely used in various industrialized countries and regions around the world. This is mainly because hot runner molds have the following notable features:

1. Shortening the molding cycle of parts

Since there is no limitation of the cooling time for the runner system, parts can be ejected promptly after solidifying.

Many thin-walled parts produced using hot runner molds can have molding cycles of less than 5 seconds.

2. Saving plastic materials

In pure hot runner molds, there are no cold runners, thus eliminating production waste. This is particularly significant for applications where plastic is expensive.

In fact, the major hot runner manufacturers worldwide experienced rapid growth during periods when oil and plastic material prices were high, as hot runner technology is an effective way to reduce waste and material costs.

3. Reducing defective products and improving product quality Variety of plastic materials

Hot runner molds have been successfully used to process various plastic materials such as PP, PE, PS, ABS, PBT, PA, PSU, PC, POM, LCP, PVC, PET, PMMA, PEI, and ABS/PC.

Any plastic material that can be processed with cold runner molds can also be processed with hot runner molds.

4. Size and weight of parts

Parts produced with hot runner molds can range from less than 0.1 grams to over 30 kilograms, making the application extremely flexible.

5. Industrial fields

Hot runner molds are widely used in electronics, automotive, medical, household goods, toys, packaging, construction, office equipment, and other industrial sectors.

Production Situation of Hot Runner Molds Internationally

In industrially advanced countries and regions worldwide, hot runner mold production is highly active, and the proportion of hot runner molds continues to increase. Many small mold shops with fewer than ten people are producing hot runner molds.

Generally, North America and Europe have been using hot runner technology for a longer time, have more experience, and a higher level of expertise.

In Asia, apart from Japan, Singapore, South Korea, Taiwan, and Hong Kong are leading the way. Although North America and Europe have higher mold manufacturing levels, their prices are higher and delivery times longer.

In contrast, Asian hot runner mold manufacturers are more competitive in terms of price and delivery times. China's hot runner mold industry is still in its infancy but is rapidly growing, with the proportion of hot runner molds continually increasing.

As hot runner technology becomes increasingly popular in China, its components are showing several main development trends:

1. Miniaturization of components

Miniaturization of components allows for multi-cavity molds for small products and multiple gate molding for large products. By reducing nozzle space, more cavities can be configured in the mold, increasing product output and the utilization rate of injection molding machines, which is crucial for the modern plastics processing industry where "time is money."

For example, the well-known MoldMasters company developed a nozzle for small parts that includes an integral heater, needle tip, and melt channel, with a diameter of less than 9 millimeters and a gate distance of only 10 millimeters, capable of molding parts weighing 1 to 30 grams.

2. Standardization of components

Currently, users are demanding shorter mold design and manufacturing cycles.

Standardizing hot runner components helps reduce repetitive design work, lower mold costs, and facilitate the replacement and maintenance of easily worn parts.

Companies like Husky, Presto, and MoldMasters have standardized nozzles, valve stems, and manifold plates for quick replacement and mold delivery. Nowadays, molds can be delivered in just four weeks abroad.

3. Reliability of design

Major mold companies at home and abroad are placing great importance on the design of hot runner plates and the connection parts of hot nozzles, focusing on pressure distribution, temperature distribution, sealing, and other issues.

The development and use of stacked hot runner injection molds are also a hot topic. Stacked molds can effectively increase the number of cavities, requiring only a 10%-15% increase in the clamping force of the injection molding machine.

Stacked hot runner molds have been industrialized in some developed countries abroad.

4. Precision of temperature control systems

Developing more precise temperature control devices for controlling the temperature of the melt in hot runner plates and gates is an effective measure to prevent resin overheating degradation and reduce product performance.

The widespread application of hot runner technology is a significant revolution in plastic molds. In injection molding, it has many incomparable advantages. As the technology matures further and manufacturing costs decrease, the significant advantages of hot runner technology will become increasingly evident.

In recent years, well-known global hot runner technology suppliers have continuously entered the Chinese market in various ways, indicating the tremendous potential of the Chinese hot runner mold market.

During the hot runner mold forming process, the temperature of the plastic melt is accurately controlled in the runner system. The plastic flows into each cavity more uniformly and consistently, resulting in parts of consistent quality.

Hot runner molded parts have good gate quality, low residual stress after demolding, and minimal part deformation. Thus, many high-quality products on the market are produced using hot runner molds. Familiar products like Motorola mobile phones, HP printers, and many plastic parts in Dell laptops are made with hot runner molds.

4. Eliminating subsequent processes, facilitating automation

Parts formed by hot runner molds are finished products, requiring no trimming of gates or recycling and processing of cold runners, thus facilitating automation. Many product manufacturers abroad combine hot runners with automation to significantly improve production efficiency.

5. Expanding the scope of injection molding processes

Many advanced plastic molding processes have been developed based on hot runner technology, such as PET preform production, multi-color co-injection, multi-material co-injection processes, and stack molds.

Despite the many significant advantages of hot runner molds compared to cold runner molds, mold users also need to be aware of the drawbacks of hot runner molds, which can be summarized as follows:

1. Increased mold cost

The price of hot runner components is relatively high, potentially increasing the cost of hot runner molds significantly.

If the production volume of parts is low and the proportion of mold tool costs is high, it may not be economically viable.

For many mold users in developing countries, the high price of hot runner systems is one of the main issues affecting the widespread use of hot runner molds.

2. High manufacturing equipment requirements

Hot runner molds require precision processing machinery to ensure integration and cooperation between the hot runner system and the mold. Otherwise, many severe problems can occur during production, such as poor plastic sealing leading to plastic leakage, damaging hot runner components, and interrupting production, or poor alignment of nozzle inserts and gates causing a significant decline in product quality.

3. Complex operation and maintenance

The application of hot runner molds is pushing the rapid advancement of technology in the Chinese mold industry.

Many emerging private enterprises in China have recognized the limitless business opportunities in this field and are establishing hot runner production companies, which is crucial for reducing the cost of using hot runner technology and accelerating its promotion and application.

However, currently, most domestic enterprises can only provide relatively basic technology, with limited options, unstable quality, and short maintenance cycles, often affecting downstream enterprises' confidence in their products.

Therefore, setting national standards for hot runner components, actively producing affordable and high-quality components, and promoting hot runner technology are key to developing domestic hot runner molds.

Compared to cold runner molds, hot runner molds are complex to operate and maintain. Improper use can easily damage hot runner parts, halting production and causing significant economic losses. New users of hot runner molds need a long time to accumulate usage experience.

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