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The Plasma Cutting Process

Plasma Cutter

Plasma cutting is a process that is most commonly used to cut steel and other types of metals of varying thicknesses.  The process uses an inert gas that is blown through a nozzle at a high speed as well as an electrical arc which is formed from the gas.  The arc is then applied to the metal that is being cut, which changes some of the inert gas into plasma.  The plasma that is created from the gas is extremely hot and can melt the metal that is being cut.

The process of plasma cutting uses a high frequency, high voltage spark which ionizes the air through the torch head to create an arc.  In order for an arc to be created the torch must be in contact with the material before starting.  The Pilot Arc method uses a two cycle approach to create plasma; this technique does not require the torch to be in contact with the material prior to starting.  A high voltage, low current circuit is used to create a high intensity spark within the body of the torch creating a small area of plasma gas.  This process is known as the pilot arc.  A pilot arc is equipped with a return electrical path in the torch head.  The pilot arc will remain lit until it is placed in the area of the material being cut, there it ignites the primary plasma cutting arc.  Temperatures of plasma arcs are incredibly hot and can reach temperatures of 45,000 degrees Fahrenheit.

Plasma cutting is a highly productive method of cutting thin and thick materials.  A hand held torch can cut steel plate up to two inches thick.  Larger torches that are controlled by using a computer are capable of cutting steel up to six inches in thickness.  Plasma cutters are an ideal method to use when metal needs to cut in a curved or angled shape.

When the process of plasma cutting was first developed, the high cost of the plasma torches meant that they could usually only be found in professional welding shops.  Since then, the price of plasma cutting equipment has dropped into the range where it is affordable for nearly every welder.  With the advancements made through the years, the weight of plasma torches has also dropped.  Older plasma cutting equipment tended to be on the heavy side, while newer models have been designed to be lighter for welders to use.  The newer models are just as powerful as the older ones, but are more convenient to carry from one job to another.

Ed C.


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