What’s A Plastic Injection Molding Machine Auxiliary Machine?

Plastic injection molding is one of the most widely used manufacturing processes for producing plastic parts with high precision and efficiency. It involves melting plastic pellets and injecting them into a mold cavity to create parts used in countless applications — from automotive components to medical devices and consumer electronics.

While the plastic injection molding machine itself is central to the process, it cannot work effectively on its own. Supporting equipment, known as auxiliary machines, play a critical role in ensuring smooth production, improving product quality, increasing efficiency, and reducing waste. These auxiliary machines handle essential tasks such as material drying, temperature control, automation, and recycling.

What Is a Plastic Injection Molding Machine Auxiliary Machine?

An auxiliary machine in the context of plastic injection molding is any piece of equipment that supports the injection molding machine by performing supplementary tasks that enable the molding process to run smoothly and efficiently. They do not perform the actual injection or molding but are indispensable for ensuring the quality and consistency of molded parts.

In a typical injection molding facility, the injection molding machine is the centerpiece. However, behind the scenes, auxiliary machines work continuously to prepare raw materials, regulate temperatures, automate handling, and recycle waste. Without these supporting devices, the injection molding process would face many challenges, including product defects, slow production rates, and high material waste.

Auxiliary machines come in various types and sizes, each designed to address specific challenges related to raw material conditioning, mold temperature maintenance, finished part handling, and more.

Why Are Auxiliary Machines Crucial in Injection Molding?

Injection molding requires tight control over multiple variables such as plastic resin moisture content, mold temperature, and cycle timing. These factors significantly impact the quality and consistency of the final product. For example, if the plastic pellets are damp, the melted plastic can contain bubbles or voids. If the mold temperature fluctuates, parts may warp or shrink unevenly.

Auxiliary machines ensure stable and optimal operating conditions by:

• Drying raw materials to remove moisture

• Precisely controlling mold temperature for better flow and curing

• Automating part removal to increase speed and reduce defects

• Recycling scrap plastic to reduce costs and environmental impact

By providing these functions, auxiliary machines enhance the injection molding machine’s capabilities and enable manufacturers to meet demanding quality standards efficiently.

Common Types of Plastic Injection Molding Machine Auxiliary Machines

1. Drying Machines

Many plastic materials, especially hygroscopic resins such as Nylon (PA), Polycarbonate (PC), and Acrylonitrile Butadiene Styrene (ABS), tend to absorb moisture from the environment. Moisture in plastic pellets is one of the biggest culprits for defects during injection molding.

When damp pellets are melted, the moisture turns into steam, causing bubbles, splay marks (silvery streaks), reduced mechanical strength, and cosmetic defects on the surface of the molded parts.

Drying machines, or dehumidifying dryers, are used to remove moisture from resin pellets before molding. They typically work by passing hot, dry air through the pellets stored in a hopper or drying chamber.

• How Dryers Work: The resin is loaded into the hopper, where heated air circulates continuously to evaporate moisture. Dehumidifying dryers often include a desiccant material that absorbs moisture from the air, maintaining very low humidity levels during drying.

• Importance: Proper drying can reduce defect rates, improve part strength and surface finish, and allow the processing of moisture-sensitive materials.

Without dryers, manufacturers risk producing parts with internal voids, weak spots, or visible blemishes — all of which may lead to customer complaints and wasted material.

2. Mold Temperature Controllers (Heaters and Chillers)

The temperature of the mold directly affects the flow behavior of molten plastic and the rate at which it cools and solidifies. If the mold temperature is too low, plastic may solidify prematurely, causing incomplete filling or rough surfaces. If too high, cycle times become longer and parts may warp or shrink improperly.

Mold temperature controllers regulate the temperature inside the mold by circulating a heating or cooling fluid through channels embedded in the mold.

• Heating Units: Used at startup or for materials that require higher mold temperatures to flow well.

• Cooling Units (Chillers): Remove heat from the mold during the cycle to speed up solidification and reduce cycle time.

• Precise Control: Modern controllers maintain mold temperatures within a narrow range, ensuring consistent part quality throughout production runs.

Maintaining an optimal and stable mold temperature helps minimize warping, shrinkage, and other dimensional inconsistencies.

3. Chillers

While chillers are a subset of mold temperature controllers, they also serve other cooling roles in the production line. These machines use refrigeration cycles to cool water or oil, which is then circulated through the mold and other equipment such as barrel heaters and auxiliary components.

• Benefits: By providing consistent and efficient cooling, chillers improve cycle time, dimensional stability, and overall process control.

• Types: Water chillers (most common) and oil chillers (for higher temperature applications).

4. Material Handling Equipment

Efficient and contamination-free transport of raw plastic pellets from storage to the molding machine is critical. Material handling auxiliary machines include:

• Vacuum loaders: Use suction to transport pellets through pipes from bulk storage to drying hoppers.

• Conveyors: Transport pellets in large quantities.

• Hoppers and Feeders: Store and regulate the flow of resin pellets into the molding machine.

Automation in material handling reduces labor costs and contamination risks, ensuring a clean, continuous supply of resin.

5. Robotic Arms and Mechanical Hands

Automated part removal systems significantly increase production efficiency by quickly and precisely removing molded parts from the machine once the cycle completes.

• Functions: Pick finished parts, place them onto conveyors or assembly lines, perform secondary operations like trimming or assembly.

• Advantages: Reduce cycle time, lower labor costs, and improve workplace safety by limiting manual handling.

• Robots are increasingly popular in injection molding for high-volume production and complex automation.

6. Granulators

Granulators recycle scrap plastic such as runners, sprues, and defective parts by grinding them into reusable granules.

• Cost Savings: Reduces the need for virgin material.

• Environmental Benefit: Promotes sustainability by minimizing plastic waste.

• Integration: Often integrated into the production line to collect scrap immediately after molding.

How Auxiliary Machines Improve Plastic Injection Mold Production

Auxiliary machines are not just “nice to have” — they are essential for optimizing plastic injection molding. Here are the key benefits they bring:

1. Enhancing Product Quality

Defects like bubbles, warping, shrinkage, and surface blemishes are common in injection molding without proper control. Auxiliary machines help minimize these problems by:

• Drying raw materials to eliminate moisture-induced defects.

• Precisely controlling mold temperatures for consistent flow and curing.

• Ensuring stable operating conditions for repeatable quality.

• The result is a lower defect rate and parts that meet exact specifications.

2. Increasing Production Efficiency

Automation through material handling systems and robotic part removers speeds up the molding cycle and allows 24/7 operation with less downtime.

Fast cooling via chillers and mold temperature controllers shortens cycle times without sacrificing quality.

Together, these improvements translate to higher throughput and more cost-effective manufacturing.

3. Reducing Waste and Operating Costs

Granulators recycle plastic scrap, significantly reducing raw material consumption.

Efficient drying and temperature control minimize scrap rates due to defects, saving both material costs and labor.

Automation reduces labor costs and human error.

4. Supporting Advanced Automation and Industry 4.0

Auxiliary machines enable injection molding plants to integrate with modern automated and digital manufacturing systems. Automated loading, temperature control, and robotic handling allow for remote monitoring, data collection, and process optimization, paving the way for smarter factories.

Conclusion

Plastic injection molding machine auxiliary machines may not perform the glamorous job of melting and injecting plastic, but they are the unsung heroes behind every successful molding operation. From drying resins and controlling mold temperature to automating part handling and recycling scrap, auxiliary machines ensure that the injection molding process runs efficiently, produces top-quality parts, and remains cost-effective.

If you are involved in plastic injection molding, understanding and investing in the right auxiliary equipment is critical. It will help you overcome common manufacturing challenges, improve productivity, and meet the high standards your customers expect.

Leading manufacturers like YEESHINE TECHNOLOGY CO., LIMITED demonstrate how leveraging advanced auxiliary machines can transform injection molding from a complex process into a smooth, automated, and highly efficient production system.

For anyone looking to optimize plastic injection mold production, auxiliary machines are not optional — they are essential.