Production thickness vs data-sheet maximum
Every manufacturer chart advertises the maximum thickness a wattage can sever. That number is real, but it is not the number to buy on: at maximum thickness the cut is slow, the edge needs rework, and a marginal focus or gas problem scraps the sheet. The table below shows both figures side by side — quote production work from the stable column and treat the maximum as reserve capability.
| Laser power | Carbon steel | Stainless steel | Aluminum | |||
|---|---|---|---|---|---|---|
| Stable | Max | Stable | Max | Stable | Max | |
| 1-2 kW | 4-6 mm | ~10 mm | 2-4 mm | ~6 mm | 1.5-3 mm | ~4 mm |
| 3-4 kW | 8-12 mm | ~20 mm | 6-8 mm | ~12 mm | 4-6 mm | ~8 mm |
| 6 kW | 15-20 mm | ~25 mm | 10-15 mm | ~20 mm | 8-10 mm | ~12 mm |
| 8-12 kW | 20-30 mm | ~40 mm | 15-25 mm | ~30 mm | 10-15 mm | ~18 mm |
| 20 kW+ | 30-40 mm | 50+ mm | 25-35 mm | 40+ mm | 15-20 mm | ~25 mm |
Copper and brass remain the exception: their reflectivity keeps practical thickness under roughly 5–8 mm even on high-power machines.
Cutting speed tables by material
Speed ranges below are IPG laser-source parameter tables (m/min). The spread inside each cell reflects assist gas, nozzle, focus, and material grade; real production usually runs nearer the low end, and a common shop rule is to quote at about 80% of the chart figure. A dash means the combination is not rated for that power.
Mild steel — cutting speed (m/min)
| Thickness | 1 kW | 1.5 kW | 2 kW | 3 kW | 4 kW | 6 kW | 8 kW | 10 kW | 12 kW | 15 kW |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 mm | 15.0-22.0 | 18.0-25.0 | 25.0-33.0 | 28.0-38.0 | 30.0-44.0 | 35.0-48.0 | 60.0-70.0 | 65.0-75.0 | 66.0-80.0 | 70.0-90.0 |
| 2 mm | 5.0-6.6 | 7.0-10 | 7.0-10 | 5.5-7.0 | 5.5-7.7 | 6.0-8.25 | 6.8-7.2 | 7.0-7.5 | 7.2-7.8 | 7.5-8.2 |
| 3 mm | 2.5-3.85 | 4.0-5.5 | 4.0-5.5 | 3.6-5 | 3.7-5.5 | 4.0-5.5 | 4.7-5.3 | 5.0-5.5 | 5.2-5.8 | 5.5-6.0 |
| 4 mm | 2.0-3.3 | 2.5-3.5 | 2.8-4.0 | 3.0-4.5 | 3.5-4.62 | 3.5-5.0 | 3.8-4.3 | 4.0-4.5 | 4.2-4.6 | 4.5-5.2 |
| 5 mm | 1.4-2.0 | 2.0-2.8 | 2.0-2.75 | 2.5-3.3 | 2.5-4.0 | 3.0-4.2 | 3.3-3.8 | 3.6-4.0 | 3.8-4.2 | 4.0-4.5 |
| 6 mm | 1.2-1.65 | 2.0-2.42 | 2.0-2.42 | 2.3-2.86 | 2.5-3.52 | 2.6-3.52 | 3.0-3.4 | 3.3-3.7 | 3.5-4.0 | 3.8-4.3 |
| 8 mm | 0.9-1.32 | 1.2-1.65 | 1.2-1.65 | 1.8-2.2 | 2.0-2.8 | 2.0-2.8 | 2.3-2.6 | 2.5-2.8 | 2.6-3.0 | 2.8-3.5 |
| 10 mm | 0.6-0.9 | 1.0-1.32 | 1.0-1.32 | 1.21-1.65 | 1.2-2.2 | 1.8-2.3 | 2.0-2.5 | 2.3-2.6 | 2.5-3.0 | 2.6-3.0 |
| 12 mm | 0.4-0.7 | 0.7-1.0 | 0.7-1.0 | 1.0-1.32 | 1.0-1.76 | 1.6-2.1 | 1.7-2.2 | 1.9-2.2 | 2.0-2.3 | 2.5-3.0 |
| 16 mm | — | 0.6-0.8 | 0.6-0.8 | 0.6-0.9 | 0.7-1.0 | 0.7-1.0 | 1.2-1.4 | 1.3-1.5 | 1.4-1.6 | 1.7-2.0 |
| 20 mm | — | — | — | 0.5-0.8 | 0.6-0.9 | 0.65-0.95 | 1.0-1.1 | 1.1-1.2 | 1.1-1.4 | 1.3-1.5 |
| 22 mm | — | — | — | — | 0.66-0.9 | 0.6-0.77 | 0.9-1.0 | 0.9-1.0 | 0.9-1.2 | 1.1-1.3 |
| 25 mm | — | — | — | — | — | 0.4-0.65 | 0.6-0.7 | 0.6-0.7 | 0.6-0.8 | 0.9-1.2 |
| 30 mm | — | — | — | — | — | — | — | — | — | 0.6-0.8 |
Stainless steel — cutting speed (m/min)
| Thickness | 1 kW | 1.5 kW | 2 kW | 3 kW | 4 kW | 6 kW | 8 kW | 10 kW | 12 kW | 15 kW |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 mm | 16.5-22.0 | 20.0-26.0 | 27.5-33.0 | 31.0-38.5 | 33.0-45.0 | 50.0-65.0 | 63.0-66.0 | 68.0-72.0 | 70.0-80.0 | 75.0-90.0 |
| 2 mm | 4.5-6.1 | 18.0-22.0 | 18.0-22.0 | 10.0-16.5 | 10.0-20.0 | 30.0-40.0 | 40.0-44.0 | 42.0-46.0 | 44.0-48.0 | 46.0-50.0 |
| 3 mm | 2.0-3.1 | 4.5-5.5 | 4.5-5.5 | 7.0-10 | 7.5-12.0 | 18.0-25.0 | 25.0-28.0 | 27.0-30.0 | 28.0-35.0 | 30.0-38.0 |
| 4 mm | 1.0-1.65 | 2.0-2.5 | 2.2-2.8 | 5.0-7.2 | 5.5-9.0 | 10.0-15.5 | 15.0-18.0 | 18.0-21.0 | 20.0-26.0 | 22.0-28.0 |
| 5 mm | 0.4-0.7 | 1.5-2.0 | 1.5-2.0 | 1.8-2.45 | 4.0-5.5 | 8.0-13.5 | 12.0-14.0 | 14.0-16.0 | 15.0-20.0 | 16.0-22.0 |
| 6 mm | 0.2-0.45 | 0.7-3.1 | 0.7-1.32 | 1.0-1.65 | 2.6-4.5 | 6.0-9.0 | 9.0-9.5 | 10.0-10.5 | 11.0-13.0 | 12.0-15.0 |
| 8 mm | — | 0.2-0.45 | 0.35-0.6 | 1.2-2.0 | 1.6-2.8 | 4.0-5.5 | 5.0-5.3 | 6.5-6.8 | 7.0-7.5 | 7.5-8.5 |
| 10 mm | — | — | — | 0.7-1.0 | 0.7-1.65 | 1.8-2.8 | 3.8-4.0 | 4.7-5.0 | 5.0-5.5 | 5.5-6.5 |
| 12 mm | — | — | — | — | 0.5-0.9 | 1.2-1.65 | 2.5-2.7 | 2.8-3.0 | 3.0-3.5 | 3.3-4.0 |
| 16 mm | — | — | — | — | — | 0.8-1.2 | 1.8-1.9 | 2.2-2.4 | 2.3-2.8 | 2.5-3.0 |
| 20 mm | — | — | — | — | — | 0.6-0.9 | 1.3-1.5 | 2.0-2.2 | 2.1-2.5 | 2.3-2.8 |
| 22 mm | — | — | — | — | — | — | 0.7-0.8 | 1.2-1.3 | 1.4-1.7 | 1.5-1.9 |
| 25 mm | — | — | — | — | — | — | 0.5-0.6 | 0.7-0.8 | 0.7-1.0 | 0.9-1.2 |
| 30 mm | — | — | — | — | — | — | — | 0.5 | 0.5-0.7 | 0.6-0.8 |
| 35 mm | — | — | — | — | — | — | — | — | 0.4-0.5 | 0.5 |
| 40 mm | — | — | — | — | — | — | — | — | 0.3 | 0.3 |
| 45 mm | — | — | — | — | — | — | — | — | — | 0.3 |
Aluminum — cutting speed (m/min)
| Thickness | 1 kW | 1.5 kW | 2 kW | 3 kW | 4 kW | 6 kW | 8 kW | 10 kW | 12 kW | 15 kW |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 mm | 10.0-13.2 | 15.0-27.5 | 25.0-31.0 | 25.0-40.0 | 26.0-44.0 | 50.0-60.0 | 53.0-65.0 | 55.0-70.0 | 60.0-80.0 | 65.0-85.0 |
| 2 mm | 2.0-4.5 | 7.0-8.6 | 10.0-13.2 | 10.0-20.0 | 10.0-22.0 | 25.0-38.5 | 30.0-40.0 | 33.0-42.0 | 35.0-45.0 | 38.0-50.0 |
| 3 mm | 0.6-1.32 | 5.0-6.5 | 5.0-6.6 | 5.0-6.6 | 8.0-12.0 | 13.0-20.0 | 15.0-23.0 | 18.0-26.0 | 22.0-35.0 | 25.0-38.0 |
| 4 mm | — | 1.0-1.65 | 1.5-2.2 | 3.0-4.0 | 4.5-8.25 | 10.0-13.2 | 12.0-16.0 | 15.0-18.0 | 17.0-24.0 | 20.0-26.0 |
| 5 mm | — | 0.6-0.9 | 1.0-1.32 | 2.0-2.65 | 3.5-5.5 | 5.0-8.8 | 7.0-10 | 11.0-15.0 | 14.0-20.0 | 17.0-22.0 |
| 6 mm | — | 0.4-0.7 | 0.6-0.9 | 1.0-1.65 | 2.2-4.5 | 4.0-6.6 | 5.0-7.0 | 9.0-11.0 | 12.0-17.0 | 14.0-18.0 |
| 8 mm | — | — | 0.4-0.7 | 0.5-0.8 | 1.2-2.0 | 2.0-3.3 | 2.5-4.0 | 4.0-6.0 | 9.0-11.0 | 11.0-15.0 |
| 10 mm | — | — | — | 0.3-0.45 | 0.8-1.65 | 1.0-2.3 | 1.5-2.8 | 2.5-3.5 | 3.5-4.5 | 4.0-5.0 |
| 12 mm | — | — | — | — | 0.6-0.9 | 0.8-1.55 | 1.0-1.6 | 1.5-2.0 | 2.0-3.0 | 2.3-3.2 |
| 14 mm | — | — | — | — | 0.3-0.66 | 0.6-0.9 | 0.8-1.2 | 1.0-1.5 | 1.5-1.8 | 1.7-2.1 |
| 16 mm | — | — | — | — | — | 0.4-1.0 | 0.6-0.8 | 0.7-1.0 | 1.1-1.4 | 1.3-1.6 |
| 20 mm | — | — | — | — | — | — | 0.5-0.7 | 0.5-0.8 | 1.0-1.2 | 1.1-1.4 |
| 25 mm | — | — | — | — | — | — | 0.3 | 0.5-0.7 | 0.7-1.0 | 1.0-1.2 |
| 30 mm | — | — | — | — | — | — | — | 0.3-0.5 | 0.5-0.7 | 0.6-0.8 |
| 35 mm | — | — | — | — | — | — | — | 0.3 | 0.4-0.5 | 0.5-0.6 |
| 40 mm | — | — | — | — | — | — | — | — | 0.3 | 0.4-0.5 |
| 50 mm | — | — | — | — | — | — | — | — | 0.3 | 0.3 |
| 55 mm | — | — | — | — | — | — | — | — | — | 0.3 |
Brass — cutting speed (m/min)
| Thickness | 1 kW | 1.5 kW | 2 kW | 3 kW | 4 kW | 6 kW | 8 kW | 10 kW | 12 kW | 15 kW |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 mm | 14.0-20.0 | 30.0-38.5 | 30.0-38.5 | 20.0-31.0 | 25.0-38.5 | 45.0-55.0 | 48.0-60.0 | 50.0-62.0 | 55.0-65.0 | 60.0-75.0 |
| 2 mm | 3.0-4.5 | 4.0-7.2 | 7.7-8.8 | 7.0-13.2 | 8.0-13.2 | 25.0-33.0 | 27.0-32.0 | 30.0-35.0 | 32.0-40.0 | 35.0-45.0 |
| 3 mm | 1.0-1.55 | 2.5-3.1 | 3.0-4.5 | 5.0-7.2 | 5.5-7.7 | 12.0-20.0 | 13.0-20.0 | 15.0-21.0 | 16.0-22.0 | 18.0-25.0 |
| 4 mm | — | 1.0-1.2 | 1.32-1.8 | 1.8-2.42 | 3.5-5.5 | 8.0-11.0 | 10.0-12.0 | 11.0-13.0 | 12.0-15.0 | 14.0-18.0 |
| 5 mm | — | 0.6-0.9 | 0.6-0.9 | 1.0-1.65 | 2.0-3.52 | 6.0-7.7 | 7.0-9.0 | 8.0-11.0 | 10.0-14.0 | 12.0-16.0 |
| 6 mm | — | — | 0.4-0.66 | 0.8-1.32 | 1.4-2.2 | 3.5-5.0 | 4.0-5.5 | 5.0-7.5 | 8.0-13.0 | 10.0-13.0 |
| 8 mm | — | — | — | 0.3-0.45 | 0.8-1.32 | 1.6-2.42 | 2.0-2.5 | 3.0-4.5 | 5.5-6.5 | 7.0-8.5 |
| 10 mm | — | — | — | — | 0.2-0.45 | 0.8-1.32 | 1.6-2.2 | 2.0-2.5 | 3.5-4.7 | 5.0-6.5 |
| 12 mm | — | — | — | — | — | — | 0.8-1.2 | 1.1-2.0 | 1.7-2.8 | 2.0-3.5 |
| 15 mm | — | — | — | — | — | — | — | 0.8-1.2 | 1.0-1.6 | 1.5-2.2 |
| 18 mm | — | — | — | — | — | — | — | — | 0.6-0.8 | 0.8-1.2 |
| 20 mm | — | — | — | — | — | — | — | — | 0.6-0.8 | 0.5-0.8 |
Reading the chart before you buy
Power does not scale linearly. Doubling wattage does not double usable thickness — from 6 kW to 12 kW, stable carbon-steel capacity moves from 15–20 mm to 20–30 mm, not to 40 mm. Buying power for speed on thin sheet is usually a better-justified spend than buying it for occasional thick plate.
Assist gas decides cost per part as much as speed. Oxygen cutting on carbon steel is faster on thick plate but leaves an oxidised edge; nitrogen leaves a clean edge on stainless and aluminum but consumption rises steeply with thickness. A machine quoted without the gas package is not a comparable quote.
The thickness you cut every day is the sizing input. If 90% of the work is 1–6 mm sheet, a 3–6 kW machine with a fast drive system outperforms a 12 kW machine on cost per part. Reserve high power for shops genuinely quoting 16 mm+ plate work.
Frequently asked
How thick can a 3 kW fiber laser cut?
On the capability chart a 3-4 kW source cuts carbon steel reliably at 8-12 mm (about 20 mm maximum), stainless steel at 6-8 mm (about 12 mm maximum), and aluminum at 4-6 mm (about 8 mm maximum).
Why is my machine slower than the chart?
Chart figures come from source-manufacturer parameter tables measured under ideal focus, fresh nozzles, and clean optics. Worn consumables, lower gas purity, and edge-quality requirements all pull real production speed down - which is why shops commonly plan at about 80% of chart speed.
Does doubling the wattage double the thickness I can cut?
No. Usable thickness grows roughly with the square root of power once the melt has to be evacuated from a deep kerf. Doubling power mainly buys speed on thin and medium sheet, not double the plate capacity.
Which assist gas should I plan for?
Oxygen for thick carbon steel where an oxidised edge is acceptable; nitrogen for stainless and aluminum where the edge must stay clean; compressed air as an economy option on thin mild steel and some aluminum. Gas choice changes both the speed column that applies to you and the running cost per hour.
Can a fiber laser cut copper and brass?
Yes, with reflective-material protection, but practical thickness stays under roughly 5-8 mm even at high power. The brass speed table above shows how quickly speeds fall with thickness.
Compare fiber laser cutting machines by working area, source power, and rated thickness, then request quotations for the shortlist with the same specification attached to each.