Insights · Setup guide
Starting to fabricate your own HVAC duct is a sequence of decisions, not a single purchase: product mix first, then the machine set, the capital budget, the workshop layout and the people. This vendor-neutral guide walks the sequence in order, with a starter-line configuration by tier at the end, so you can scope the project before you talk to any supplier.
Every other decision flows from this one. HVAC duct is round (spiral lockseam or welded) or rectangular, and the two are made on completely different equipment. Round duct dominates industrial ventilation, dust extraction and a growing share of architecturally-exposed commercial work; rectangular dominates commercial supply and return air in many markets. Decide which your local market buys most and build that line first — you can add the second within a year or two. For the cross-section trade-off see round vs rectangular duct, and for how round duct itself is made see spiral vs welded round duct.
For round (spiral) duct, the heart of the shop is a spiral tubeformer fed by a decoiler and a run-out table — coil strip in, continuous lockseam tube out. Add a roll bender and a seam welder for heavy-gauge, stainless and fittings. See the spiral machine buyer's guide and the spec comparison.
For rectangular duct, you have two routes. A coil-fed auto duct line integrates decoiling, levelling, notching, punching, shearing and folding into one PLC-controlled flow — highest throughput, fewest operators. Or build it from standalone machines: a shear and folder (or a coil line), a Pittsburgh lockformer for the longitudinal seam, a TDF/TDC flange former for the connections, and corner and cleat machines. See the auto duct line buyer's guide, the lockformer guide and the TDF flange guide.
Shared across both, most shops keep a plasma or laser cutter for blanks and fittings, and the relevant duct welders (spot, stitch, seam) for the joints a lockseam cannot make.
Scope the money before you fall in love with a machine. As a rough order of magnitude: a Pittsburgh lockformer is in the low five figures (USD), a TDF flange former five figures, a spiral tubeformer roughly US$30,000–150,000+, and a full coil-fed auto duct line a six-figure investment — before tooling, freight and commissioning. Work from delivered-and-commissioned cost and five-year total cost of ownership, not the sticker price. The full breakdown is in the duct machine cost guide, the 5-year TCO model and the ROI & payback guide.
A duct line is long and linear: a spiral cell needs a clear run for the decoiler, former and run-out table plus space to store coil and stage finished duct; a rectangular auto line needs similar length plus coil handling. Get the material flow right — coil in at one end, finished duct out the other, with no back-tracking. Most machinery runs on 380V three-phase (50Hz, or 60Hz for some export markets); connected power runs from a few kW for a lockformer to 15–22 kW for a large spiral former and more for a full line — size your supply and breakers from the nameplate, not a guess (see duct machine power requirements). Add compressed air for pneumatic clamping and a crane or forklift for coil handling. A good supplier provides a 2D layout drawing sized to your floor before you buy.
Modern duct lines need fewer people than buyers expect. A spiral former or an auto duct line is typically run by a single trained operator, with one or two more for finishing, handling and packing — that labour reduction is the core of the automation business case, worked through in duct shop labour & throughput economics. Budget for operator training (a good supplier includes it in commissioning) and a refresher within the warranty period.
Confirm what your market specifies before you buy, because it dictates seam type, gauge and leak class: SMACNA in North America and much of the export world, EN 1505/1506 in Europe, AS/NZS 4254 in Australia and New Zealand, DW/144 in the UK. See international duct standards compared. Buy machines whose output meets the standard your customers require, and keep the documentation — it matters at handover.
Send every shortlisted supplier the same brief — product type and size mix, gauge and material, your country's voltage and frequency, and your port — and ask for a delivered-and-commissioned price with a two-year spare-parts list, commissioning and training included. Verify published specifications against the delivered machine. Work through the 47-point buyer's checklist and read the common buying mistakes and used vs new before committing. If you are importing, the international import guide covers lead times, Incoterms and customs.
| Tier | Typical machine set | Best for |
|---|---|---|
| Entry (round) | Spiral tubeformer + decoiler + run-out table | A new entrant serving round-duct ventilation demand at lowest entry cost |
| Entry (rectangular) | Shear + folder + Pittsburgh lockformer + TDF former + corner/cleat | Standalone-machine rectangular shop, lower capital, more manual |
| Mid | Auto duct line (rectangular) or spiral cell + roll bender + seam welder (round) | Established fabricators scaling one product line for throughput |
| Full | Coil-fed auto line + spiral cell + welding cell + cutting + flange/corner | A complete shop serving both round and rectangular from one floor |
Indicative configurations only — the right set depends on your product mix, volume and market. SBKJ supplies all of the above as matched modules and will size a line to your floor with a layout drawing before you commit.
Get a shop layout & line recommendation in 12 hours →
For round duct: a spiral tubeformer with decoiler and run-out table, plus a roll bender and seam welder for heavy/stainless and fittings. For rectangular: either a coil-fed auto duct line, or standalone machines — shear and folder (or coil line), Pittsburgh lockformer, TDF/TDC flange former, and corner and cleat machines. Most shops also keep a plasma or laser cutter. Start with the product your market buys most.
A modest standalone rectangular shop can start in the low-to-mid tens of thousands of US dollars; a spiral round cell is typically US$40,000–150,000+; a full coil-fed auto line is six figures (roughly US$120,000–500,000+), before tooling, freight, commissioning, building and power. Budget on delivered-and-commissioned cost and 5-year TCO — see the cost guide.
A spiral line plus decoiler and run-out table needs a clear run of roughly 12–20 m plus storage and staging; a rectangular auto line needs similar length plus coil handling. Most machinery runs on 380V/50Hz three-phase (60Hz for some export markets); connected power ranges from a few kW for a lockformer to 15–22 kW for a large spiral former and more for a full line. Plan compressed air and a crane or forklift for coils.
Fewer than buyers expect. A spiral former or auto duct line is typically run by one trained operator, with one or two more for finishing, handling and packing. That labour reduction is the core automation business case.
Start with whichever your local market buys most. The spiral round cell has the lowest entry cost and fastest single-product throughput; a rectangular auto line has the broadest commercial demand. Many shops start with one and add the other within a year or two.
Planning a new duct shop or a second line? Send your product mix, target volume and floor size — an SBKJ mechanical engineer replies within 12 hours with a machine set, a layout drawing and a delivered-and-commissioned budget.
Ask an engineerSBKJ supplies the complete shop as matched modules: spiral tubeformers, auto duct lines, TDF flange & lockformers, welding and cutting & forming — or browse the full catalog.
