Plasma cutting blows an ionised gas jet through electrically conductive metal, melting and expelling the material. It is fast, cheap on thick plate and works only on conductive material. Where laser stops being economical on thickness, plasma usually takes over, and where edge quality matters most, laser usually wins back the work.
Where plasma sits between laser and waterjet
Laser gives the best edge and accuracy up to its thickness limit. Plasma is faster and much cheaper on thick plate but leaves a rougher edge with a slight bevel and a heat affected zone. Waterjet cuts anything, conductive or not, with no heat at all, more slowly and at higher cost. Most fabrication shops keep two of the three and subcontract the other.
Edge quality and what to expect
A plasma cut edge carries a small bevel angle, some dross on the underside depending on parameters, and a hardened heat affected zone a fraction of a millimetre deep. High definition plasma systems narrow all three considerably. If the edge is to be machined, tapped or welded to a close fit, allow stock or specify a different process.
What drives the price
Cutting speed, which is high, plus pierce time per hole, plus consumable wear, which is a real cost on plasma because electrodes and nozzles are consumed. Material is priced by the plate consumed, so nesting matters. And the secondary operations: deburring and dross removal are labour, and they are frequently the reason a cheap cut becomes an expensive part.
Design notes
Keep hole diameters at or above roughly the plate thickness, because small holes cut poorly and can be badly tapered. Allow for the bevel on parts that stack or mate. Expect the heat affected edge to be harder, which matters if the part is later tapped or formed close to the cut. And where a tight tolerance is needed, plan to machine that feature afterwards.
Questions people ask about plasma cutting companies
What can plasma cut?
Electrically conductive metals: mild steel, stainless and aluminium being the common ones. It cannot cut non conductive materials, which is where waterjet is used instead.
Is plasma cheaper than laser?
On thick plate, usually much cheaper and faster. On thin sheet, laser is generally better and often cheaper once edge quality and secondary operations are counted.
Does plasma leave a bevel?
Yes, a small one, and it varies with parameters and thickness. High definition systems reduce it, and parts that must mate closely should allow for it or be machined.
Why do holes come out tapered?
Small holes relative to plate thickness are the hard case for plasma. As a rule keep hole diameter at or above the plate thickness, or drill them instead.