Plasma Cutter Functions
A plasma torch is essential in plasma cutters to cut metals. Plasma which is the fourth state of matter has to be created for it to work. Plasma is a super-heated (15,000 degrees Celsius) substance that is a gas and a liquid at the same time. Two things are required to create plasma: gas and heat source.
Plasma cutters use inert gases (often compressed air) and electricity to create plasma. The plasma cutting equipment is set up so that it creates an electric circuit with the metal that is being cut. When the end of the torch is touched to the metal, the circuit is created and a spark flashes through the nozzle of the plasma torch.
This spark travels to the negative electrode in the torch handle and meets with the rapidly flowing inert gas. When the gas comes into contact with the electricity it is heated to around 15,000 degrees Celsius and becomes plasma. The plasma surges out of the tiny nozzle and onto the surface that you want to cut.
The tiny opening in the nozzle focuses the plasma flow and causes it to speed up. It is the speed, temperature and focus of the plasma that enables it to cut metal almost as well as a laser. As long as everything is set up properly, the cuts can be very clean with little noticeable affect on the rest of the work piece.
Since a plasma cutter’s function requires an electric circuit they can cut pretty much anything that conducts electricity including copper, aluminum and stainless steel. Even cheap plasma cutters will work in the same way.
The old versions of plasma cutters (plasma cutting was invented during World War II) started the arc with high frequency, high voltage circuits. This means that the operator risked electrocution if they were not careful. Also, these old machines are difficult to repair and maintain.
A plasma cutter can cut metals of different thicknesses. The size of the machine is what determines the sever cut. “Sever cut” is the standard used to define the thickest possible cutting potential for a given plasma cutter. The thicker the metal to be cut the easier it is for a CNC plasma cutter to operate. You have to watch out though, the closer the metal thickness comes to the sever cut rating of a plasma cutter the messier the cut may be. This means you may have to clean up the edges after you are finished cutting.
