Compressed Air in Plastic Duct Manufacturing: The Hidden Driver of Efficiency

In the industrial sector, the manufacturing of plastic ducts for electrical, agricultural, or communication applications requires more than just raw materials and molds—it demands precision, consistency, and efficiency. At the core of this process lies a component that often goes unnoticed yet is absolutely essential: the air compressor.

Thanks to its ability to deliver a steady and controlled airflow, rotary screw compressors—such as the CBS XV Custom—enable molding, cooling, and automation in duct manufacturing at speeds and quality levels that would otherwise be unattainable. From internal air-blowing during extrusion to powering cutting and coiling systems, compressed air truly becomes the driving force of the production line.

This article outlines how the process works, the competitive advantages it provides, and why selecting the right compressor can mean the difference between a standard duct and a high-performance industrial product.

Detailed Process of Plastic Duct Manufacturing with Compressed Air Support

1. Dosing and Mixing

Raw Materials: Pellets of PVC, HDPE, or LDPE are used.

Additives: Colorants, UV stabilizers, and plasticizers are incorporated depending on the duct’s application.

The mixture is prepared in hoppers or blenders prior to extrusion.

2. Extrusion

• The blended material is fed into an extruder, where a rotating screw heats and melts the plastic.
• The molten polymer is pushed through a die (cylindrical, oval, or corrugated) to form the duct.

Role of the Compressor:

In hollow ducts, compressed air is injected inside the molten tube to maintain its shape as it exits the die.

This technique is known as internal air-blown extrusion.

3. Calibration and Cooling

The newly formed duct passes through a vacuum calibration tank to ensure uniform diameter.

Compressed air is used to:

• Power vacuum systems that shape the duct.
• Accelerate cooling via directed air streams.
• Pressurize molds in corrugated duct production.

4. Haul-Off and Cutting

A haul-off unit (belts or rollers) pulls the duct at a constant speed.

The duct is then cut automatically to the required length (e.g., 3 m sections or 50 m rolls).

In some cases, compressed air also powers pneumatic cutting blades.

5. Coiling or Stacking

• Flexible ducts are automatically coiled with the aid of pneumatic drives.
• Rigid ducts are stacked for packaging and transport.

Why Is the Air Compressor Critical in This Process?

• Maintains the internal shape of hollow ducts.
• Improves surface finish quality.
• Reduces production cycle times by accelerating cooling.
• Increases precision in cutting and final packaging.

Enables automation through pneumatic actuators.

Did You Know?

A 50-meter plastic duct can be produced in under 2 minutes with a rotary screw compressor such as the CBS XV Custom. This is possible thanks to its continuous, stable airflow, which ensures consistent extrusion and speeds up the cooling process.

The results?

Fewer cycles per hour

Higher throughput with the same equipment

More precise ducts with no deformations