A plasma torch (as well as known as a plasma arc, plasma gun, or plasma cutter, plasmatron) is an instrument for generating a straight flow of plasma. The plasma jet can be utilized for applications including plasma cutting, plasma arc welding, plasma spraying and plasma gasification for waste disposal.
High speed and precise cutting technology combined with low cost, makes the plasma cutter one of the very useful tools not only in large-scale industrial applications but also to small hobbyist shops.
The plasma cutter is an excellent device for using in most cutting applications. It can cut both ferrous and nonferrous materials, but it is especially perfect for those in which cut quality and speed are important.
Usually, fabrication work is done by hand, using a hand held plasma torch. There are various types of plasma torch depending on what thickness of metal you’re likely to be cut.
Besides this, CNC plasma cutter also has very extensive applications in the metal industry, which cut profiles from digital files onto larger sheets of metals.
Using a plasma cutter in the metal working process is much lower cost than water-jet or laser cutter. The cutting work by a plasma cutter is also a very quick and precise process.
Thermal plasmas are produced in plasma torches by direct current (DC), alternating current (AC), radio-frequency (RF) and other discharges. DC torches are the most commonly utilized and analyzed, because when compared to AC: “there is less flicker generation and noise, a more stable operation, better control, a minimum of two electrodes, lower electrode consumption, slightly lower refractory [heat] wear and lower power consumption”.
In a DC torch, the electric arc is created between the electrodes (which can be made of copper, tungsten, graphite, molybdenum, silver etc.), and the thermal plasma is developed from the continual input of carrier/working gas, bulging outward as a plasma jet/flame (as can be seen on the right). In DC torches, the carrier gas can be, for example, either oxygen, nitrogen, argon, helium, air, or hydrogen; and although termed as such, it does not have to be a gas (thus, better termed a carrier fluid).
For instance, a research plasma torch at the Institute of Plasma Physics (IPP) in Prague, Czech Republic, functions with an H2O vortex (as well as a small addition of argon to ignite the arc), and produces a high temperature/velocity plasma flame. In fact, previous studies of arc stabilization employed a water-vortex. Overall, the electrode materials and carrier fluids have to be specifically balanced to ignore excessive electrode corrosion or oxidation (and contamination of materials to be treated), while keeping up ample power and function.
Furthermore, the flow-rate of the carrier gas can be elevated to uphold a larger, more projecting plasma jet, provided that the arc current is adequately increased; and vice versa.
The plasma flame of a real plasma torch is a few inches long at most; it is to be distinguished from fictional long-range plasma weapons.
