Plasma Cutters - How Do They Work?
A plasma cutter can pass through ferrous metals like a hot knife through butter, thanks to the unique properties of plasma.
So, what exactly is plasma? Plasma is the fourth state of matter. Many places teach that there are three states of matter; solid, liquid and gas, but there are actually four. The fourth is plasma. To put it very simply, a plasma is an ionized gas, a gas into which sufficient energy is provided to free electrons from atoms or molecules and to allow both species, ions and electrons, to coexist. If you boost a gas to extremely high temperatures, you get plasma. The energy begins to break apart the gas molecules, and the atoms begin to split. When the fast-moving electrons collide with other electrons and ions, they release enormous amounts of energy. This energy is what gives plasma its unbelievable cutting power.
Plasma cutters work by sending a pressurized gas through a small channel in the cutting nozzle. In the center of this channel, there is a negatively charged electrode. When you apply power to the negative electrode, and you touch the tip of the nozzle to the positively charged metal, the connection creates a circuit and a very powerful spark. As the gas passes through the channel, the spark heats the gas until it reaches the fourth state of matter, plasma. The plasma temperature can reach an incredible 30,000o F -- making a plasma cutter capable of cutting through almost anything.
Plasma cutters work by creating a high velocity plasma flow between a negatively charged electrode and a positively charged one.
One of the advantages of using a plasma cutter is that the surface of the metal outside of the cutting area remains relatively cool; this prevents the warping and paint damage that can occur with other flame cutters. Plasma cuts up to five times faster than traditional torches and does not rely on highly-flammable gases. Many plasma cutters also perform well as gougers and can pierce metal quickly and accurately.
Plasma cutters are now a staple of industry. In CNC (computer numerically controlled) plasma cutting, you can arrange your shapes on a computer screen and cut them automatically and efficiently.
