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10.1 Fundamentals of Plasma Cutting
A plasma can be created by adding energy to an electrically neutral gas. In the case of air plasma cutting the
air is dry, clean compressed air delivered from an air compressor or an air line. By adding electricity through
an electrode (Hafnium), the gas becomes imbalanced and conducts electricity. The greater the level of
electricity the higher the temperature of the plasma.
Plasma cutting torches control energy by constricting the arc and forcing it through a constricting nozzle fitted
to the torch. By increasing air pressure and intensifying the arc with higher voltages, the arc becomes hotter
and more capable of blasting through thicker metals and blowing away the cuttings, leaving minimal cleanup.
10.2 Process Operation
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Compressed air flows through the torch.
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A pilot arc is established inside the head of the plasma torch.
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The high voltage of the pilot arc changes the air stream into a plasma stream.
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The plasma stream is constricted and forced through a tip with a small orifice.
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The constricted plasma stream exiting from the tip is termed a plasma jet.
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The plasma jet is allowed to touch the work.
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An arc is initiated between the hafnium electrode and the work.
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The arc passes through the orifice of the tip.
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The constricted arc so formed is a stiff, columnated and narrow arc.
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The intense heat of arc melts the plate.
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The plasma jet blows away the metal to produce a cut.
Cross Section of Plasma Torch
Airflow
Constricting nozzle
Electrode
Constricted Plasma Stream
Workpiece
Summary of Contents for BOC Raptor CUT 30C
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