Laser Cutting by Material
What each material family needs — assist gas, typical thickness range per power class, and the factors that move cut speed.
Mild steel / carbon steel
Cut with oxygen or high-pressure air. Oxygen gives a smooth, weldable edge on 3–12 mm steel; air is faster but leaves a rougher edge. A 3 kW fiber laser holds about 8 mm in production; 6 kW reaches 12–16 mm, and 12 kW extends to roughly 30 mm.
Stainless steel
Cut with high-purity nitrogen (or air for non-critical edges). The oxygen edge left by CO2 lasers needs post-processing; nitrogen on fiber leaves an oxide-free edge that goes straight to welding or passivation. 3 kW handles about 8 mm, 6 kW about 12 mm.
Aluminum
Nitrogen assist, and expect a higher power threshold than steel because aluminum reflects and conducts heat away quickly. 3 kW gives about 6 mm, 6 kW about 10–12 mm. Clean the oxide layer before cutting to avoid inconsistent piercing.
Copper and brass
The hardest common metals to cut on a near-infrared fiber laser: copper absorbs poorly at 1064 nm and conducts heat away fast. Speed is a fraction of stainless on the same power. 6 kW cuts about 4–6 mm brass; copper needs more power or should be considered for a different process.
| Material | Assist gas | Typical production range (3 kW) | Typical production range (6 kW) |
|---|---|---|---|
| Mild steel | O₂ | 0.5–8 mm | 1–16 mm |
| Stainless | N₂ | 0.5–8 mm | 1–12 mm |
| Aluminum | N₂ | 0.5–6 mm | 1–12 mm |
| Copper / brass | N₂ | 0.5–3 mm | 1–6 mm |
These are planning ranges, not machine limits. For material-specific settings see the thickness and speed chart and the 304 vs 316 stainless guide.
For independent background on sheet-metal laser cutting, see The Fabricator; for machine ranges from an equipment maker, see Trumpf.