How Plasma Cutters Work

By: Robert Valdes

Where Saws Failed

This is what plasma cutting looked like in 1980.
This is what plasma cutting looked like in 1980.

In World War II, U.S. factories were cranking out armor, ordnance, and aircraft almost five times faster than the Axis powers. This was largely thanks to private industry's tremendous innovations in the field of mass production.

One area of innovation rose out of the need to cut and join aircraft parts more efficiently. Many factories working on military aircraft adopted a new method of welding that involved the use of an inert gas fed through an electric arc. The breakthrough discovery was that charging the gas with an electric current formed a barrier around the weld, which protected it from oxidation. This new method made for much cleaner lines at the joints and much sturdier construction.


In the early 1960s, engineers made a new discovery. They figured out that they could boost temperatures by speeding up the flow of gas and shrinking the release hole. The new system could reach higher temperatures than any other commercial welder. In fact, at these high temperatures, the tool no longer acted as a welder. Instead, it worked like a saw, cutting through tough metals like a hot knife through butter.

This introduction of the plasma arc revolutionized the speed, accuracy and types of cuts manufacturers could make in all types of metals. In the next section, we'll examine the science behind this system.