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Estimate kerf width and material loss for plasma, laser, waterjet, and oxy-fuel cutting. Uses the 1.5× orifice diameter rule for plasma. Includes CNC kerf compensation offset.
| Process | Kerf Range | Typical | Notes |
|---|---|---|---|
| Laser (CO₂/Fiber) | 0.1–0.5 mm Narrowest | 0.3 mm | Very consistent kerf, minimal test cutting needed |
| Waterjet | 0.2–1.0 mm Narrow | 0.4–0.6 mm | No HAZ, excellent edge quality, slight jet divergence on thick plate |
| Plasma — Fine Cut | 0.4–1.5 mm Medium | 0.9 mm | HD plasma tables; more consistent than standard; 1.5× orifice formula applies |
| Plasma — Standard | 1.0–3.0 mm Medium | 1.8 mm | Most shop plasma systems; use 1.5× orifice rule; test cut for critical nesting |
| Plasma — High Amp | 3.0–6.0 mm Wide | 4.0 mm | 100A+ systems on thick plate; edge bevel typically 1–3° |
| Oxy-Fuel | 1.5–5.0 mm Widest | 2.5 mm | Thick structural plate only; edge requires dressing for tight fit-up |
Kerf ≈ 1.5 × 1.4 mm = 2.1 mm. For a 610 mm (24") cut: material lost = 2.1 × 610 = 1,281 mm³. CNC offset = 1.05 mm. Always verify with a test cut before running production parts.
Typical kerf = 0.3 mm (consistent for most fiber lasers on mild steel under 12mm). For a 500 mm cut: material lost = 0.3 × 500 = 150 mm³. CNC offset = 0.15 mm. Laser kerf is highly repeatable — less test cutting needed than plasma.
Typical kerf = 0.4–0.6 mm (no HAZ, excellent edge quality). For a 305 mm (12") cut: material lost = 0.5 × 305 = 152 mm³. CNC offset = 0.25 mm. Kerf widens slightly with thicker material due to jet divergence.
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Try Quote Writer Free →Kerf is the width of the slot cut by the plasma arc — the material that is vaporized and blown away during cutting. For most shop-level plasma cutters, kerf ranges from 1–3 mm depending on the nozzle size, amperage, and material thickness. The kerf must be compensated in CNC nesting so finished parts end up the correct size.
Enter half the measured kerf value as kerf compensation in your CNC controller. If your plasma cuts a kerf of 2 mm, offset the tool path by 1 mm outward on outside cuts (and inward on inside cuts) so the finished part is the programmed size. Always verify with a test cut — measure the result and adjust.
Laser cutting generally produces the narrowest kerf, typically 0.3 mm for most fiber or CO₂ lasers cutting steel. Waterjet is second at 0.2–0.5 mm. Plasma is wider at 1–3 mm for standard systems (0.4–0.8 mm for fine-cut plasma). Oxy-fuel has the widest kerf at 2–5 mm due to the flame width.