A plasma cutter is a tool that is used to cut hard metals such as steel into precise, clean pieces. It has been in use since World War II and is an extremely efficient metal working tool. Most plasma cutters that are used in factories are operated mechanically, but hand held devices are available. Plasma cutters are able to create relatively clean, slag free cuts in metal and are often programmed to cut out repeated designs in large factories. Plasma cutters are often used to cut thinner plates of metal due to the angle of the arch created. These tools often resemble welders in design as the first plasma cutter was developed from a welder.
How does a plasma cutter work?
A plasma cutter uses matter called plasma to cut through the metal. Plasma is ionized gas and is extremely hot. Plasma is a state of matter that can be achieved by super heating. Scientifically we understand that when heat or energy is applied to molecules it causes them to move more quickly stretching and breaking of free of the bonds that hold them together. In solid matter the molecules are exposed to less heat and so they are tightly bonded together. As the solid is exposed to heat or energy the bonds begin to loosen and the solid becomes liquid. If more heat or energy is applied the liquid becomes a gas as more bonds are escaped and broken. If the gas is further heated the bonds break down further and the matter becomes plasma.
The plasma used in a plasma cutter is generated when gas or air is blown at very high speed through a nozzle. The tool also simultaneously generates an arc of electricity from the negative electrode in the nozzle to the metal (which is magnetic). The arc of electricity passes through the high pressured gas and superheats the gas to turning it into plasma. To create the charge required to turn gas into plasma the gas is passed through a narrow channel which has a negatively charged electrode at the bottom. When the plasma cutter is turned on and supplied with power this electrode becomes charged and when its tip comes in contact with the metal to be cut a circuit is created which results in a spark. This spark heats the gas turning it into plasma. This plasma stream is then used to cut the metal at high temperature and speeds. The smaller the opening of the plasma cutter the hotter the resulting plasma and the easier and more precisely it cuts through metal.