What a Fiber Laser Welder Does for a Duct Shop
A fiber laser welding machine fuses metal with a focused infrared beam instead of an electric arc. The beam is narrow, the energy density is high, and the total heat input is low — so joints are joined fast, distortion stays small, and thin stainless or aluminium stops moving under the weld. Preda's LW series covers three powers — LW-1500, LW-2000 and LW-3000 — in handheld or automated configuration, for steel, stainless and aluminium, with published list pricing from around $8,500, CE certification and a 2-year warranty.
For a duct fabricator this is the productivity step up from TIG. Hand-guided TIG is a skilled, slow craft: every joint is filler-fed arc work, and on thin stainless the heat input warps what you just welded. A laser welder joins the same materials several times faster, mostly autogenous, with cleanup reduced to almost nothing — one operator covers the work of several TIG stations.
The LW Series at a Glance
Published figures for the Preda LW-series laser welding machines, with the practical meaning alongside.
| Parameter | Published figure | What it means on your floor |
|---|---|---|
| Models | LW-1500 / LW-2000 / LW-3000 | Three powers on one platform; pick by material thickness and duty |
| Laser power | 1,500 W / 2,000 W / 3,000 W | Higher power buys thickness and speed, not better thin-gauge quality |
| Configuration | Handheld / automated | Handheld goes to the part (fittings, repairs); automated runs production seams |
| Material | Steel, stainless steel, aluminium | The duct-shop material set, thin gauges included |
| Laser source | Fiber laser with parameter control | Stored parameter sets per material and gauge; repeatable welds shift to shift |
| Construction | Heavy-duty steel frame | Vibration-free operation; factory rates 10+ year service life |
| Certification / warranty | CE / 2 years | European safety compliance, factory warranty, parts support |
As with any build-dependent machine, the quotation — not the brochure — is where your numbers live: beam delivery, focus optics, cooling capacity, wire feeder option and chiller rating all vary by configuration. Ask for them in writing.
1500W vs 2000W vs 3000W — Matching Power to Thickness
More power is not a free upgrade. On thin sheet, excess power means distortion problems and a wider bead; too little power on thick stock means lack of penetration. Class-typical targets for duct gauges:
| Model | Comfort zone (autogenous) | Class-typical travel speed | Typical duct work |
|---|---|---|---|
| LW-1500 | Stainless up to ≈1.5 mm; steel ≈2 mm | ≈1.0–2.0 m/min on 1 mm stainless | Kitchen exhaust, spiral duct seams, fittings |
| LW-2000 | Stainless up to ≈2 mm; steel ≈2.5–3 mm | ≈0.8–1.5 m/min on 1.5 mm | Mixed stainless and galvanized fabrication |
| LW-3000 | Stainless ≈3 mm; steel ≈3–4 mm | ≈0.5–1.2 m/min on 3 mm | Heavier exhaust, structural duct, flange work |
These figures are class-typical ranges for fiber laser welding at these powers, not machine-specific guarantees — the real answer comes from a trial weld on your own stock. Two practical rules: buy power for the thickest joint you run regularly, not the worst case you see once a quarter; and remember that a 3000 W machine run at 1500 W settings still does 1500 W work, so stepping one model up is insurance rather than waste.
Handheld vs Automated — Which Configuration
The configuration question is really "where does the work come to the machine?"
- Handheld — the head goes to the part: fitting attachment, corners, repairs, short seam runs, anything on a table too big or too awkward to move. The learning curve is short; output depends on operator technique, so plan on training and a parameter card per joint type.
- Automated — the part comes to the machine: production seams, duct sections, repeated components. The head is fixtured, travel is mechanised, and bead quality becomes independent of the operator. This is the right choice when you run the same joint hundreds of times a week.
Most duct shops end up mixed: an automated station for the volume seam work and a handheld unit for fittings and assembly. Ordering both on the same power platform keeps consumables, optics training and service common.
Where It Earns Money in Duct Fabrication
- Round duct seams. Longitudinal and fitting seams on spiral and welded duct, joined faster than any arc process — pair with your spiral tubeformer and elbow station.
- Kitchen exhaust. Thin stainless exhaust duct welded fast, flat and clean, where TIG's heat input would warp the panels.
- Clean room and pharma. Precision, low-distortion welds on stainless systems that must hold their leakage class.
- Fitting and assembly. Handheld unit on gorelocker output, branch fittings, damper frames and repairs.
Safety, Fume Extraction and Installation
Laser welding adds requirements a TIG shop may not have met yet:
- Eye protection. The beam is invisible and the wavelength — around 1070–1080 nm — passes straight to the retina. Handheld work needs wavelength-rated eyewear and screens; automated cells need a Class 1 enclosure or a screened booth. This is not optional, and it is checked at inspection.
- Fume extraction. Welding galvanized stock vaporises zinc; stainless adds chromium and nickel compounds. Local extraction at the head with filtered discharge is mandatory for operator exposure, and usually for compliance.
- Electrical and cooling. A 3000 W laser welder draws roughly 10–12 kW at the wall, and the source needs its chiller on a stable supply. Have an electrician size the circuit before the machine ships.
- Floor and access. Handheld work needs a stable, grounded table; automated stations need levelled foundations and service access around the cell.
Factory Audit & Purchasing Checklist
- Trial weld on your stock. Ship your thinnest and thickest production material; require welded samples back together with the parameter sets used.
- Penetration evidence. Visual acceptance is not enough — ask for bend tests or macro-sections showing root fusion on your gauge.
- Speed achieved, not promised. Travel speed on 1 mm stainless is the number that decides payback; measure it in the trial.
- Consumables and optics. Nozzle, protective lens, collimating and focusing optics — prices, expected life and change procedure. Optics damage is the most common surprise cost.
- Chiller and power scope. Included or excluded? Voltage and phases available in your plant; confirm the machine's real input power.
- Safety package. Eyewear, screens, enclosure class, extraction interface — in writing, with the CE file.
- Service path. Remote diagnostics, local agent, spare-parts shipping, response time — contractual terms, not sales promises.
Common Faults and Troubleshooting
| Symptom | Likely cause | First response |
|---|---|---|
| Porosity | Contaminated or oily edges; zinc vapour trapped; insufficient shielding gas | Degrease edges; adjust gas flow and angle; slow travel slightly |
| Lack of penetration | Power too low for the gauge, focus position wrong, travel too fast | Check focus on a test coupon; raise power or slow travel per parameter card |
| Undercut or sunken bead | Travel too fast, beam angle off, joint gap too wide | Reduce speed; check joint fit-up and gap tolerance |
| Distortion on thin sheet | Heat input too high, insufficient clamping | Step down power; add clamping; use a skip-weld sequence |
| Spatter and bead irregularity | Contaminated optics, focus drift, coating variation on the stock | Clean or replace the protective lens; re-check focus; segregate coated stock |
| Sudden power drop | Optics contamination, fiber connector issue, cooling fault | Check chiller and alarms; inspect optics; call service with the alarm log |
FAQ
How much faster is it than TIG, really?
On thin stainless duct work, several times faster per joint is the class-typical answer — the gain comes from travel speed and the elimination of filler feeding and post-weld cleanup. Your trial weld will put the number on your own joints.
Can an operator move from TIG to handheld laser work?
Yes, and usually faster to production speed than TIG, because the machine controls penetration. What transfers is joint fit-up discipline; what is new is focus distance and parameter selection.
What thickness range does it cover?
Across the three powers, roughly 0.5 mm up to 3–4 mm depending on model and joint type. Below 0.5 mm, distortion control dominates; above 4 mm, arc processes regain their advantage.
How does it compare with a dedicated seam welder?
Different jobs. A longitudinal seam welder is a dedicated station that fuses duct seams at line speed; the LW series is a general welding tool for seams, fittings and assembly. Shops that need both, buy both.