A plasma cutter is a tool which is used to cut steel and other metals of varying thickness. It harnesses the power of the ‘plasma’ to efficiently pass through thick metal sheets and make precise cuts.

What is plasma?  The Science behind the Plasma Cutters

Plasma is the fourth state of matter, beyond the gaseous state, which makes its presence felt by heating the gas even more.  The heat energy begins to break apart the gas molecules and the atoms begin to split. As we all know, the atoms are made of protons and neutrons in the nucleus surrounded by electrons. In the plasma state, the electrons get separated from the nucleus and they move around freely leaving behind the positively charged nuclei- the ions. When these fast moving electrons collide with other ions and electrons, they release vase amounts of energy and this energy is what contributes to the superb piercing ability of the plasma.

Working of plasma cutters

In a plasma cutter, an electric arc is made to pass through a highly pressurised inert gas like nitrogen, argon or even air.  This increases the temperature of the gas to about 30000 degrees Fahrenheit so that it ultimately reaches the plasma state. The electrode which produces the arc, is negatively charged and when the tip makes contact with the positively charged metal to be cut, an electric circuit is formed. The stream of plasma helps in conducting the electric current from the arc to the metal. This helps in melting the metal at the point of contact; the gas helps in clearing away the molten metal.

The shielding gas controls the width of the plasma beam.

A diagrammatic representation of plasma cutter

CNC (Computer Numerical Controlled) Plasma cutting uses the personal computer to create the shapes to be cut and direct the cutting machine. It is similar in operation to a plotter in that it has two axes that synchronize with each other to produce artistic shapes of any design- making them useful in creating plasma art.

Benefits

There are numerous benefits of employing plasma cutters to cut and shape metals.

• The cutting time is very less. Hence, the work is finished quickly.

• The HAZ (heat-affected zone) is small. Hence, the surface of the metal outside the cutting area remains relatively cool.

• It does not need oxygen or fuel, as with other metal cutters like acetylene torches.

• The cut is sharp, smooth and even.

Drawbacks

The main drawback of using plasma cutters is-

• Its use is restricted only to the conducting material like metals or alloys. Non conducting materials like wood and plastic cannot be cut in this way.

• The electrodes are prone to wear and tear and require periodic replacement.

Availability and Use

Plasma cutters come in all shapes and sizes. The plasma cutters are used extensively in the construction, welding and art industry.

In Construction:  Plasma cutters are used to shape the metallic parts and cut away unwanted pieces. They also used by plumbers and automobile manufactures.

In Welding:  Plasma cutters find use in the welding industry in joining metal ends.

In Art: Artists use small, portable plasma cutter to make intricate designs in metals.

                                                                                                                                                 A plasma cutter in action

ESAB Welding and Cutting Products, located in the United States of America is the world’s leading manufacture of plasma cutting machines and equipment.