Plasma cutting, sometimes known as plasma arc cutting, is a melting process. In this process, a jet of ionized gas is used at temperatures over 20,000°C is employed to melt the material and expel it from the cut.

During the plasma cutting process, an electric arc strikes between an electrode and workpiece (or cathode and anode respectively). The electrode is then recessed in a gas nozzle which has been cooled, limiting the arc and causing the narrow, high velocity, high-temperature plasma jet to be created.

How Does Plasma Cutting Work?

When the plasma jet is formed and hits the workpiece, recombination occurs, causing the gas to change back to its original state and it emits intense heat throughout this process. This heat melts the metal, ejecting it from the cut with the gas flow.

Plasma cutting can cut a broad variety of electrically conductive alloys such as plain carbon/stainless steel, aluminum and aluminum alloys, titanium and nickel alloys. This technique was initially created to cut materials that could not be cut by the oxy-fuel process.

Key Advantages of Plasma Cutting

  • Plasma cutting is comparatively cheap for medium thickness cuts
  • High-quality cutting for thicknesses up to 50mm
  • Maximum thickness of 150mm
  • Plasma cutting can be carried out on all conductive materials, in contrast to flame cutting which is only suitable for ferrous metals.
  • When compared to flame cutting, plasma cutting has a significantly smaller cutting kerf
  • Plasma cutting is the most effective means of cutting medium thickness stainless steel and aluminum
  • Faster cutting speed than oxyfuel
  • CNC plasma cutting machines can offer excellent precision and repeatability.
  • Plasma cutting can be carried out in the water which results in smaller heat-affected zones as well as minimizing noise levels.
  • Plasma cutting can cut more complex shapes as it has high levels of accuracy. Plasma cutting results in minimal dross as the process itself gets rid of excess material, meaning very little finishing is required.
  • Plasma cutting does not lead to warping as the fast speed significantly reduces the heat transfer.

Main Disadvantages of Plasma Cutting

  • Plasma cutting results in a much larger heat affected zone than laser cutting (however, as previously mentioned, this can be mitigated by cutting in water)
  • With thinner sheets and plates the quality is not as good as with laser cutting
  • Laser cutting is more precise
  • Cannot cut thicknesses as high as waterjet or flame cutting
  • Plasma cutting causes a wider kerf than laser cutting

The Bottom Line

Plasma cutting has many advantages and can be highly beneficial in many applications. plasma cutting has more robust capabilities and is cost-effective, however, in some instances, it may not be as accurate as other forms of cutting.

Masteel offers high precision plasma cutting which transfers minimal heat to the profiled steel, decreasing the heat-affected zone.

If you would like to find out more about plasma cutting and how it is used, get in touch with Masteel for more information.