Switching from 4 kW to 6 kW Laser: A 40% Throughput Case Study
A Wenzhou sheet-metal shop upgraded their 4 kW fiber to a 6 kW LS-3016. 90 days in, here's what changed — and what didn't.
Background
The customer ( anonymized as "Jinhe Sheet Metal") runs a 12-machine shop in Wenzhou, serving HVAC ducting and electrical enclosure fabricators. Their old 4 kW fiber laser ran 2 shifts, 6 days a week, but was the bottleneck — every quote was capped by laser capacity.
In March 2026 they replaced the 4 kW with our LS-3016 (6 kW, Bessel head, dual-pallet shuttle).
What Changed
Daily throughput: 1.6 t → 2.3 t
That's a 44% uplift on the same nesting library, same operators, same part mix.
Cut capacity: 20 mm → 25 mm mild steel
The 4 kW could cut 20 mm MS reliably but struggled on 25 mm — work that went to plasma cutting at lower edge quality. The 6 kW handles 25 mm at acceptable edge quality for the structural enclosure market.
Pierce time on 20 mm: 0.8 s → 0.3 s
Bessel focusing head + 6 kW power. On nested jobs with 4,000+ pierces per sheet, this alone saved 32 minutes per shift.
What Didn't Change
- Operator count: Still 1 operator + 1 helper per shift. The shuttle table didn't reduce staffing, it reduced idle time.
- Material yield: Same 87% as before. Nesting was already efficient.
- Scrap rate: 1.8% → 1.7%. Marginal — most scrap was operator error, not machine.
Surprises
Gas consumption went UP
With the 4 kW, the customer ran N₂ at 1.5 MPa. To realize the 6 kW's potential on thick plate, they bumped N₂ to 2.2 MPa. Liquid N₂ cost went from ¥1,800/week to ¥3,100/week.
Lesson: Higher-power lasers need higher assist-gas pressure to cut clean. Budget for it.
Edge quality exceeded expectations on stainless
The Bessel head's stable focal length produced visibly cleaner edges on 8 mm 304 stainless — the customer now quotes cosmetic-grade enclosure work they previously outsourced.
The Numbers
| Metric | 4 kW (before) | 6 kW LS-3016 (after) | Δ |
|---|---|---|---|
| Daily throughput | 1.6 t | 2.3 t | +44% |
| Max MS thickness | 20 mm | 25 mm | +5 mm |
| Pierce time @ 20 mm | 0.8 s | 0.3 s | -63% |
| Liquid N₂ cost | ¥1,800/wk | ¥3,100/wk | +72% |
| Shifts running | 2 | 2 | same |
| Operators/shift | 2 | 2 | same |
Payback
Machine price premium (4 kW → 6 kW LS-3016): about $38,000.
Added revenue from +0.7 t/day capacity: ~$420/day at average $600/t gross margin.
Payback: ~91 days.
Final Take
For shops already running fiber lasers at 4 kW with consistent bottleneck, the jump to 6 kW with a modern focusing head pays back in under a quarter — IF your work mix includes thick plate (16+ mm) or high-pierce-count nesting.
For shops doing thin sheet (< 3 mm) with low-pierce-count parts, the upgrade isn't worth it. The 4 kW is already ceiling-bound by rapids and nesting, not laser power.
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