Loading …
Two thermal cutting methods — and when you choose one over the other
Where the metal fabricator previously cut plates with a saw, cutting shears or a gas flame, most modern workshops today have CNC-controlled plasma or laser cutting available. Both methods are thermal — they melt or evaporate the material along a cut line — but they work differently and each has their strengths.
With plasma cutting an electrically conductive gas is led through a nozzle where it is ionized to plasma at very high temperature. The ionized gas jet melts the metal while a gas stream blows the melted material away through the cut. Plasma is especially strong on thicker material and can cut relatively quickly with good efficiency even in plates over six millimeters.
With laser cutting a powerful laser beam is focused to a very small point which melts or vaporizes the material while an assist gas — for example oxygen or nitrogen — blows the melted material out of the cut. The laser beam's narrow and precise focus gives a very accurate cutting line with a neat cut which often requires little aftertreatment.
| Property | Plasma | Laser |
|---|---|---|
| Best for | Thicker material | Thin to medium-thick plates |
| Precision | Good, but coarser cut edge | Very high, often under one tenth of a millimetre |
| Investment | Lower purchase price | Higher purchase price |
| Post-processing | Often necessary deburring | Often minimal post-processing |
The choice depends on material thickness, requirements for cut quality, material type and production volume. If the requirement is a fast, robust cut of thick structural steel, plasma is often the obvious choice. If thin, complex details must be cut with a clean cut and minimal post-processing, it points towards laser. Many workshops end up having both technologies available because the tasks vary.