Plasma Cutting is simply the process of cutting metals of different sizes using a plasma cutter. These machines normally run from a compressed air supply which is forced through a small nozzle at the end of the cutting torch. This air has an electrical charge passed through it which flows from the torch to the surface of the metal and turns this air supply into plasma. It is this that cuts the metal
Today's plasma cutters feature inverter power sources, more commonly known as IGBT's (Inter Gate Bi-Polar Transistors). These have the added advantage of being more energy efficient and reliable than older power module technology such as MOSFET. This is one of the reasons why plasma cutters are no longer as expensive as they were.
Many plasma cutters now use a system called High Frequency Pilot Arc. This is a process of producing a plasma jet without the need to make contact with the metal surface (like many still do). This is where a small spark is ignited within the air supply at the end of the torch to produce a fairly small plasma jet. There is a return electrical feed built into the torch head to allow a circuit to be completed. Upon contact with the work the main plasma jet (or arc) jumps to the metal and produces the main cutting jet.
The use of plasma cutters can significantly speed up the process of metal cutting when compared to traditional methods such as Oxy-Acetylene. Trades such as vehicle dismantling and de-commissioning have benefitted from the use of this technology.
Many units are within reach of the home or DIY user and have the added advantage of being lightweight and portable. Most can now run from domestic air compressors and have low cost replacement consumable arts that are used at the end of the torch as things like the sparking electrode and cutting tip wears out.