My Plasma Cutter Won't Arc

Plasma cutters remove metal material by using a high-voltage electrical arc inside a stream of compressed air. The electrical arc melts the metal at an extremely high temperature while the compressed air stream blows the material out of the way. Newer models of plasma cutters use an onboard air compressor for the stream of air. Older and larger plasma cutter models require a separate air source to provide the air stream.

  1. Inspect the air compressor's pressure to ensure the correct amount is being sent to the plasma cutter. Almost all models have an internal pressure switch that prohibits the unit from turning on unless the proper amount of air pressure is provided to the machine.

  2. Check all electrical connections for the supply power and the required ground clamp. Plasma cutters operate on variable voltages that range from 120 volts alternating current (VAC) up to 240 VAC. Make sure the correct voltage is being sent to the machine. The plasma cutter must have a good electrical ground attached to the work piece that is being cut. A loose wire or bad ground connection will interfere with the unit turning on to make an arc.

  3. Clean the torch tip of metal debris. Many times, during the cutting process, slag from the cut material will build up on the torch tip. The slag interferes with making good electrical contact with the work piece.

  4. Replace worn or burned internal torch tip parts. There are several parts to the torch tip to make a good arc for the plasma cutter. If one of these parts are burned or creates restricted airflow for the plasma arc, the arc cannot be established.

  5. Wipe the metal work piece of all foreign debris with a rag. Oil and grease residue may still reside on the metal surface of the work piece, creating resistance to the plasma arc.