Plasma Cutters

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Plasma cutters are an amazing piece of technology that might sound like it was invented in the movies, but it was actually discovered and honed during WWII. When factories were producing armor, artillery, planes and tanks, they were moving production along at a blazing pace. A new method of welding was developed that married the use of inert gas fed through an electric arc. It turned out that the electrical current allowed a rust-free barrier around the weld. In the 1960s engineers came up with the idea of funneling electrified gas through a small aperture and raising the rate of gas released through the hole. The result was higher temperatures, which meant the welder was no longer a welder; it could actually cut through steel like a knife.

The way this works is relatively easy science. Heating gas to extremely high temperatures gives you plasma. The atom is made of protons and neutrons in a nucleus, which are surrounded by a swarm of electrons. Heated atoms discharge ions that are formed from positively charged nuclei, and these release the electrons from the atom. They are then moving so quickly that when they bang ...
... into other electrons and ions, they release huge amounts of power. This is plasma. Plasma cutters harness the power of the plasma into a cutting point that can melt through steel. They work by sending an electrical arc through shop air, nitrogen, oxygen or argon, which is then passed through a narrowed opening. The electrical arc raises the temperature of the gas to a state of matter where it is neither solid, liquid or gas, but plasma. This innovation led to a precision and speed with which metal could be cut and formed, which had never before been seen in the industrialized world.

There are many types of plasma cutters. Huge cutters that use robotic arms are found in the aeronautic and automotive industries, as well as for the manufacture of heavy machinery. Custom auto body shops can craft the parts they need, and the automotive industry itself can create such heavy-duty components as chassis and frames for cars and trucks. They range all the way down to small, hand-held tools that you might use for home applications. While they were once too expensive for the average consumer to even contemplate owning, they have become common enough for the price to be less prohibitive.

No matter what their size, they are all comprised of basically the same parts. There is an electrode in the center, with a nozzle on the end that releases the plasma through a swirl ring. A second set of channels releases a steady flow of shielding gases around the cutting area, controlling the radius of the plasma beam. Today plasma cutters contain a pilot arc between the central electrode and nozzle to ionize the gas as a primer, prior to the transfer through the narrowed opening. Referred to as consumables, there are parts such as the electrode and the nozzle that will wear out from the intensive application and need replacing every so often.