What Is an Auto Duct Line 5?
An auto duct line 5 is an integrated roll-forming production line that converts galvanized steel coil into finished rectangular HVAC duct sections. The "5" refers to the five processing stations arranged in sequence: decoiler & leveler, TDF flange forming, bead/cleat locking, notching and fly cutting. Instead of running sheet metal through five separate machines with manual handling between each step, the coil feeds continuously and one or two operators receive finished duct at the output end.
For duct fabricators producing more than roughly 3,000 m² of duct per month, the difference between a manual shop and a 5-station line is not only labor cost — it is dimensional consistency, flange edge quality and the ability to quote tight delivery windows.
Station-by-Station Process Flow
1. Decoiler and leveler
The coil is loaded on a powered decoiler (typically 3–5 t capacity) with an expansion mandrel. A leveling unit removes coil set and crossbow so the sheet enters the flange station flat. Uneven feeding is the single most common cause of flange height variation, so pay attention to the leveler roll count — seven or more working rolls handle thin-gauge material far better than four.
2. TDF flange forming
The sheet edges are roll-formed into the TDF (TDC) flange profile. On a quality line the flange is produced by hardened duplex rollers with a closed bead, giving a repeatable flange height of around 21 mm. Look for a quick-change roller set: if you switch between 0.5 mm and 1.0 mm galvanized sheet frequently, tooling changeover time directly determines your uptime.
3. Bead and cleat locking
The longitudinal bead (and drive/S-cleat where applicable) is formed before the duct is closed, which stiffens the panel and allows the seam to be locked without buckling. This is the station that separates true production lines from simple flange folders.
4. Notching and corner preparation
Corner notches are punched automatically so the duct can be closed into a rectangle without hand grinding. Accurate notch geometry is what makes the final corner tight enough to assemble with a hand seamer.
5. Fly cutting
A servo-driven fly shear cuts the duct to the programmed length, typically 1,200 mm standard sections, while the line keeps running. CNC control with stored part programs lets the operator recall sizes instead of re-entering dimensions.
Key Technical Specifications to Compare
| Parameter | Typical value | Why it matters |
|---|---|---|
| Material | Galvanized steel 0.5–1.2 mm | Confirms the line covers the full HVAC gauge range |
| Coil width | 1,250 mm / 1,500 mm | Determines maximum duct dimension |
| Duct length | 1,200 mm (standard) | Matches site installation practice |
| Line speed | 8–15 m/min | Drives daily output and labor efficiency |
| Flange type | TDF / TDC, height ~21 mm | Compatibility with your existing duct standards |
| Total power | ~25–35 kW | Electrical supply planning |
| Operators | 1–2 | Real labor cost per finished duct |
Output and Payback Logic
A well-set-up auto duct line 5 typically produces 1,500–2,500 m² of duct per shift. Compare that with manual fabrication, where a team of six produces a fraction of the same volume with more scrap. When you request a quotation, ask the supplier for output figures at your material thickness and duct size — speed figures quoted at the thinnest gauge are rarely achievable in daily production.
Factory Evaluation Checklist
- Roller material: request tool steel (e.g. GCr15 or equivalent) hardness specs; soft rollers lose tolerance within months.
- Control system: ask for the PLC brand and whether part programs can be stored and recalled.
- Expansion and service: confirm the number of stations that can be added later (U-shape, spiral, elbow making) without replacing the main frame.
- Commissioning: insist on running your own coil on the machine before shipment.
- Documentation: electrical drawings, roller drawings and a training session for two operators.
Common Questions From Buyers
Can the line handle aluminum as well as galvanized steel? Yes, but ask for roller finishing and feed settings tuned for aluminum, which is softer and marks more easily.
How much floor space is required? Plan for roughly 18–22 m of straight run plus coil handling clearance and finished-duct stacking area.
Is a spiral duct line a better investment? For large-diameter round duct, yes. For rectangular ductwork, which dominates commercial HVAC, the 5-station line remains the most flexible choice.
Conclusion
An auto duct line 5 is a capacity decision, not just an equipment purchase. Evaluate it on roller quality, control system, real output at your gauge, and the supplier's willingness to test with your own material. Get those four right and the line will pay back through labor savings and consistent flange quality within the first production year.