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PLASMA CUTTING AND GOUGING

Basic principles

Conductive gas to transfer energy from an electrical power source trough a plasma-cutting torch to the material being cut.

Inside the plasma torch the arc is struck between the cathode (electrode - polarity) and an anode (tip + polarity) As compressed air is introduced in the arc, plasma is produced and forced out trough the tip with high kinetic velocity, forming what is referred to as the pilot arc. Upon impact with the positive pole of the work piece the arc is transferred from electrode / tip to electrode work piece following the plasma gas. Due to the design of the torch tip this arc and the high velocity of flow of free

Pilot arc

electrons and ionized particles called the plasma jet is constricted to a very small cross section with high-energy concentration. In the impact zone the high inherent energy of the jet, consisting of heat, ionization energy and dissociation energy is released, creating temperatures up to 28000°C (50000°F). The high velocity air plasma jet will efficiently melt and blow away practically any electrically conductive material, and provide a narrow smooth cut.

The basic plasma cutting equipment consists of a constant current DC power supply, an arc starting circuit (High frequency or air type) and a torch.

Transferred arc

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