air ring extrusion

Types of air ring extrusion

An air ring extrusion is a device used in manufacturing to produce extruded products like the polyethylene foam. The air ring consists of a series of holes through which air is blown into the extruded product. This results in the formation of the final product. The two main types of air rings are air dilating rings and air cooling rings.

• Air cooling rings: This is an air ring extrusion that has upward-blowing vents in the shape of a crescent. Air cooling rings are most suitable for processing materials with high melting points like polypropylene, polyester, etc. The ring provides instant cooling of the extruded product to maintain its shape and dimension. An air cooling ring can be used in conjunction with water spray or air/water combo for more effective cooling.
• Air dilatation rings: also known as air rings or water-air rings, are air rings that have downward-blowing holes. An air dilatation ring is specifically designed to increase the diameter of an extruded product through the inflation process. It does this by circulating hot air around the product. The thrusters of cold air that come out of the air dilatation rings give the extruded product a final finish while also ensuring that it is stable. Air dilatation rings are often used with water rings to provide the gage of a sock or a film.

Specification and Maintenance

• Material:

  A substantial factor influencing air rings' performance is the material used in their construction. It's crucial that the material selected possesses a high resistance to thermal variations and is capable of withstanding elevated temperatures. Typically, materials like stainless steel, brass, or aluminum alloys are favored for air rings, particularly for air cooling rings.

• Design:

  The design of an air ring entails the configuration of its shape and dimensions, factors that significantly impact how the air flows as well as the cooling rate of the extrudate. Commonly, air rings exhibit a circular shape, yet the precise dimensions can vary depending on the particular application requirements. Additionally, dual or even multiple-slot designs are now trending, greatly enhancing the cooling efficacy of the air rings.

• Cooling Efficiency:

• Temperature Control:

  Air rings possess the ability to regulate the temperatures of the cooling air, a capability that is of paramount significance. This function not only directly impacts the cooling rates of the extrudates but also exerts an essential influence over the quality of the final products. Therefore, businesses must choose air rings equipped with advanced temperature control systems. Such systems ensure the cooling temperature can be adjusted to meet various process requirements, thereby guaranteeing the quality of the final products.

• Maintenance:

  To ensure stable operation and a long service life, it is vital to carry out regular maintenance of the air ring. This includes regularly checking and cleaning the cooling holes of the air ring to avoid blocking and ensure smooth air flow. Meanwhile, pay attention to the working condition of the temperature control device of the air ring, regularly inspecting whether it is working normally and whether the setting is reasonable, and timely adjusting it to ensure that the cooling temperature is in the appropriate range. In addition, regularly inspecting the fixed components of the air ring to ensure that its fastening parts are not loose is also critical. Air rings of different materials and designs may require specific maintenance methods and schedules. Therefore, it is imperative to consult the relevant instructions for the particular model of the air ring and implement maintenance procedures accordingly.

Scenarios of using air ring extrusions

There are multiple industries that use plastic extrusion technology to manufacture products.

• Flexible PVC hose industry

  The flexible PVC hose is a common product manufactured using air ring extrusion. A hose can have many applications, such as in plumbing, medical piping, automotive, agriculture, manufacturing, and construction. In these industries, flexible PVC hoses can be used for water and gas supply, transporting fluids and materials, protecting wires and cables, drainage, and also as flexible connectors between different equipment and machinery.

• Food and beverage industry

  In the food and beverage industry, there's a constant demand for packaging products such as bottles, containers, and film. Air ring extrusion is used to create the packaging as well as piping and tubing for efficient production and supply. Using flexible PVC hoses in food processing systems helps in the transportation of food products, ingredients, and liquids. The flexible tubing also provides safe pathways for the transfer of food products, reducing the risk of contamination.

  A major consideration in the application of air ring extrusion in this industry is to choose the right material that meets food safety standards.

• Construction industry

  The construction industry uses PVC air ring extrusion to produce window and door profiles, pipes, and drainage systems. Flexible drainage pipes created by this technology can be used for cable protection pipes, water drainage, and irrigation systems. Through efficient and economical production methods, air ring extrusion helps meet the construction industry's increasing requirements for quality, durability, and functionality.

• Automotive industry

  The automotive industry can use air ring extrusion to produce automotive components like seals, gaskets, tubing, and wiring harness conduits. Flexible PVC tubing is used in automotive systems to protect wires and cables, convey fluids, and implement lightweight solutions without compromising performance.

• Electrical and communication industry

  In the electrical, wiring, and telecommunications industries, flexible PVC tubing is used to protect electrical wires and communication cables. Flexible PVC hoses produced by air ring extrusion have the required strength, flexibility, and chemical resistance to protect sensitive wires from environmental hazards. They also ensure signal integrity and system reliability by preventing electromagnetic interference.

How to choose air rings for extrusion

When choosing an air-ring component for a plastic-extrusion job, several factors must be taken into consideration. These include the raw material, production capacity, cooling requirements, air-ring design, compatibility, and budget constraints.

• Raw material: Different types of plastics require distinct cooling techniques. For instance, APET extrusion cooling rings will differ in structure from those designed for PVC. Therefore, selecting an air ring specifically designed for a particular plastic material is essential. This choice ensures optimal cooling to achieve the desired product quality.
• Production capacity: The extrusion speed impacts the dimensions of the air ring. If the production rate is high, a larger air ring with more cooling stations may be necessary. This will ensure that the plastic products are cooled properly within a short time. Conversely, if the production capacity is lower, a smaller air ring could be sufficient.
• Cooling requirements: Different products have varying cooling needs depending on their wall thickness and the material used. An air ring with a more suitable cooling arrangement should be selected to ensure efficient solidification and minimize warp.
• Air-ring design: Various air-ring designs are available, each with its features and advantages. Consider the specific application requirements and choose an air ring that meets them.
• Compatibility: It's vital to consider whether the air ring is compatible with the extrusion die and downstream equipment. This is significant for maintaining smooth operation and efficient processing.
• Budget constraints: While air rings play an important role in the extrusion process, it is also necessary to consider budget constraints. Carefully evaluate the cost-performance ratio of different air rings and choose the one that best balances performance and cost according to financial limits.

Q&A

Q: What are the latest developments in air ring extrusion technology?

A: One of the latest developments in air ring extrusion technology is the recent trend toward compact air rings. Such air rings utilize a well-insulated cooling chamber to ensure effective cooling of the extrudate while minimizing the quantity of cooling air needed. Furthermore, the introduction of quick-change liners into air rings is also a recent technological advancement. Quick-change liners allow operators to adjust to various product specifications more rapidly and easily, enhancing production flexibility and efficiency.

Q: What are the tips for maintaining an air ring extrusion?

A: Regular cleaning of the air ring is essential to maintain its performance and product quality. Additionally, periodic inspection of the air ring for wear or damage should be carried out. This way, any potential issues can be identified and addressed early enough, thus preventing costly repairs and downtimes. More importantly, lubricating the adjustable components of the air ring can ensure smooth operation and maintain the stability of the processing.

Q: How does an air ring extrusion affect product quality?

A: The cooling rate of the air ring can significantly impact the physical properties of the product, such as its strength and toughness. Moreover, the shape and size of the cooling jacket in the air ring can affect the dimensional accuracy of the product. This includes factors such as the tolerance and the surface quality.