Laser Cutting Tolerance Guide

Dimensional Accuracy

Modern fiber lasers with linear drives hold ±0.002"–0.004" over the full sheet (5' x 10') on thin material. On individual features: ±0.002" is standard, ±0.001" is achievable on small parts cut slowly. Accuracy degrades on thick material — at 0.500" steel, ±0.005" is production-realistic. At 1", ±0.008"–0.010". These are practical numbers, not machine spec numbers.

Hole Accuracy

Laser-cut holes: ±0.003" on diameter for holes 1x–3x material thickness. Holes smaller than material thickness are problematic — the beam dwells and creates taper. Best practice: design holes ≥ 1.5x material thickness for clean, round results. On thin material (< 0.125"), holes down to 0.040" are achievable with pulse cutting.

Kerf Width

Fiber laser kerf: 0.006"–0.012" depending on power and material thickness. CO2 laser kerf: 0.008"–0.020". The software compensates automatically, but designers should be aware of minimum web width: 1.5x material thickness between adjacent features. Narrower webs will melt, distort, or fall away during cutting.

Flatness & Distortion

Laser introduces localized heat — thermal distortion is real on thin material with dense cut patterns. Sheet 20 ga and thinner with features closer than 0.500" apart may bow or warp. Mitigation: nitrogen assist (less heat), optimized cut sequencing, and stress-relief cuts. Parts destined for brake press forming rarely have flatness issues because the forming process resets the shape.

Edge Quality

Nitrogen-assisted cutting produces a clean, oxide-free edge suitable for welding or finishing. Oxygen-assisted cutting on mild steel produces a thin oxide layer that aids weld penetration but may affect paint adhesion. Fiber laser edges are slightly rougher than CO2 on thick material (> 0.500") due to the shorter wavelength. Edge quality is generally Ra 63–250 μin depending on speed and thickness.

Taper & Perpendicularity

Laser-cut edges are typically perpendicular to within 0.5° on material up to 0.500". On thicker material, slight taper (1°–2°) may appear. CO2 lasers generally produce more perpendicular edges on thick material than fiber. If edge perpendicularity matters, specify it — shops can slow the cut to improve it.