Coil Processing for HVAC & Ducting Fabrication
Duct fabrication shops burn through GI sheet — and buying pre-cut sheets from a service center means paying someone else's processing margin on every square metre. Fabricators above a threshold volume bring coil processing in-house: a decoiler and CTL line converting GI coil into duct blanks at coil prices.
Friend Engineering Works builds the coil-processing front end for HVAC fabricators: compact CTL lines for duct-gauge GI, slitting capability for coil-fed duct lines, and the decoilers and handling equipment that complete the cell.
Duct Shop Processing Economics
The spread between GI coil price and cut-sheet price in India typically runs several rupees per kilogram. A duct shop consuming a few hundred tonnes a year recovers a compact CTL line's cost from that spread alone — while gaining control over sizes (cut exactly the blank the job needs, not the merchant's standard sheet) and eliminating supply waits.
Recommended HVAC Processing Setup
| Element | Specification |
|---|---|
| Material | GI 0.5–1.6mm (22g–16g duct gauges) |
| CTL line | Compact, with leveler, ±0.5mm length accuracy |
| Decoiler | 3–10 tonne, manual or motorized to suit coil supply |
| Optional slitting | For coil-fed duct lines and TDF flange strip |
| Output | Duct blanks sized per job; slit coil for auto duct lines |
Feeding Automated Duct Lines
- Coil-fed duct lines (auto duct lines) need slit coil at the machine's working width — a slitting line lets one master coil feed multiple duct line widths
- Plasma/laser-fed shops use CTL blanks — a leveler in the line keeps blanks flat on the cutting table
- TDF/TDC flange systems consume narrow slit strip — produced economically as edge programs on the same slitting line
Recommended Equipment
- Cut to Length Line — We manufacture advanced Cut to Length Lines for uncoiling, straightening, gauging, cross-cutting to length, and stacking work.
- Slitting Line — Friend Engineering Works slitting lines are designed to ensure the highest standards of quality and productivity while processing different materials.
- Decoiler Machine — Our decoiler machines are designed for efficient and safe uncoiling operations with heavy-duty construction.
Frequently Asked Questions
At what volume does in-house coil processing make sense for a duct shop?
As a rule of thumb, fabricators consuming roughly 20–30 tonnes of GI per month recover a compact CTL line investment quickly from the coil-vs-sheet price spread, size flexibility and eliminated supply delays. We can work the calculation with your actual volumes and local prices.
What GI gauge range do HVAC lines need to cover?
Commercial duct work spans roughly 0.5mm to 1.2mm (24g–18g), with heavier 1.6mm for industrial and kitchen exhaust duty. Our compact CTL lines for HVAC are specified for 0.5–1.6mm GI as standard.
Do you supply complete lines or individual machines?
Both. Many duct shops start with a decoiler and CTL line, adding a slitting line when they install automated duct lines. All equipment is designed to integrate, so the cell grows without replacing earlier machines.