Plasma cutting
What settings for 3 mm steel on Plasma cutting?
Quick answer
For 3 mm mild steel on Plasma cutting: 40 A at a steady 60–70% of max travel speed — slow enough to sever clean, fast enough to avoid wide drossy kerfs.
Settings table by thickness
| Output | Clean cut (steel) | Severance |
|---|---|---|
| 40 A | ~10 mm | 14 mm |
| 60 A | ~16 mm | 22 mm |
| 80 A | ~22 mm | 30 mm |
| 100 A+ | ~28 mm+ | 38 mm+ |
Dialling it in
Start at the middle of the band on scrap of the same thickness. Listen: a consistent bacon-crackle means the voltage/wire-speed pair is right; hissing spatter means mismatched. Watch the wetting at the toes — a bead sitting proud on top is too cold; one digging in and undercutting is too hot.