Spiral duct forming machines are essential equipment in modern HVAC duct manufacturing. They are designed to produce high-strength, airtight, and cost-efficient spiral ducts, widely used in commercial buildings, industrial ventilation systems, and clean-room air distribution.
In this guide, we explain what a spiral duct forming machine is, how it works, its key components, the advantages of spiral ducts, and what buyers should evaluate before purchasing a machine.
What Is a Spiral Duct Forming Machine?
A spiral duct forming machine, also known as a spiral tubeformer, is an industrial machine used to manufacture spiral-shaped air ducts from galvanized steel, stainless steel, or aluminum coils.
It forms the duct by continuously wrapping metal strip into a spiral tube while interlocking the seam to produce a strong and airtight duct.
Where Spiral Ducts Are Commonly Used：
- HVAC ventilation systems
- Industrial exhaust systems
- Airport and subway ducting
- Clean rooms and laboratories
- Commercial building air distribution
How Does a Spiral Duct Forming Machine Work? (Full Working Principle)
The working principle of a spiral duct forming machine can be summarized into five major stages:
1. Coil Loading and Feeding
The machine begins by feeding a metal strip from a coil — typically galvanized steel (GI), stainless steel, or aluminum.
Steps:
- Place the coil onto a decoiler
- Feed the strip into the forming head
- The material is clamped and ready for profiling
2. Strip Forming and Profiling
Before the metal becomes a duct, the strip edges pass through profiling rollers to create a shape that can interlock during the spiral process.
What happens here:
- Edge shaping
- Bead formation (for strength)
- Seam preparation
This ensures the final tube will have a strong mechanical lock.
3. Spiraling and Seam Locking
This is the core of the working principle.
The strip wraps around a forming head at a precise angle while the machine simultaneously locks the seam.
Key actions:
- Metal strip rotates around the forming mandrel
- Strip angle determines duct diameter
- Seam interlocks into a tube lock, welded lock, or knurled lock
- Continuous forming creates endless duct length
This creates a rigid and airtight spiral duct without welding.
4. Cutting to Length (Automatic)
Once the duct reaches the required length, an automatic flying cutter or plasma cutter trims it cleanly without stopping production.
Cutting options:
- Standard saw blade cutter
- Plasma cutter (for thicker material)
- Flying cutter for continuous operation
This ensures high precision and smooth tube ends for easy installation.
5. Discharge and Tube Collection
The finished spiral duct is discharged onto a rack or roller support and ready for stacking.
Optional automation:
- Tube support rack
- Automatic stacking system
- Labeling system
Key Components of a Spiral Duct Forming Machine
To help buyers understand the equipment better, here are the main parts of a modern tubeformer:
Components List
- Decoiler / Coil Feeder
- Feeding rollers
- Profiling & forming rollers
- Forming head (mandrel)
- Seam locking system
- Cutter (saw or plasma)
- Control unit (CNC/PLC)
- Tube support table
Advantages of Spiral Ducts Made by Tubeformers
Spiral ducts dominate HVAC projects due to their:
1. High structural strength
The spiral seam adds ring-like reinforcement.
2. Excellent air-tightness
Less leakage → greater energy savings.
3. Faster installation
Longer lengths reduce joints.
4. Aesthetic appearance
Often used exposed in commercial buildings.
5. Lower cost compared to rectangular ducting
Lower labor and material consumption.
How to Choose a Spiral Duct Forming Machine (Buyer Guide)
Key specifications to check:
- Diameter range (e.g., 80–1600mm)
- Steel thickness (0.4–1.2mm GI)
- Max speed (30m/min to 50m/min)
- Lock seam type
- Machine power and forming stability
- Cutter type
- CNC control options
- After-sales and spare parts availability
Spiral Duct Machine Applications in HVAC Industry
A spiral duct forming machine is widely used in:
- Commercial HVAC projects
- Ventilation for warehouses and factories
- Subway and airport ducting
- Underground parking systems
- Clean-room air handling systems
FAQ About Spiral Duct Forming Machines
Galvanized steel, stainless steel, aluminum, and mild steel.
With proper maintenance, 8–12 years or longer.
Standard machines: 12–35 m/min
High-speed machines: 40–60 m/min
Recommended for producing thick ducts or when cut-end quality is critical.
Main wear parts: cutters, forming rollers, lubricants — low operating cost.