Plasma Cutting Tips Part 4
One of the problems associated with plasma consumable life is related directly to technique. One of the most frequently abused features of a plasma cutter that results in marked reduction in consumable life is the over use or misuse of the pilot arc. The pilot arc is the arc that is generated when the trigger is held, without it being in close proximity to the metal. The pilot arc is used to help generate continuity between the work piece and the torch. It works great for starting cuts, and for cutting expanded metal. This arc is generated by a grounded circuit between the torch head and the consumable itself, and the return path for the torch is made back through the unit via the torch consumables which are also tied to a small ground wire. The pilot arc is a reduced amperage arc which helps conserve the plasma consumables. But because the heat is concentrated on the consumable itself, instead of the work piece, the consumable is sacrificed fairly quickly. “Blank” firing the torch in the air will eat up consumables at a fast pace. Reducing the Pilot Arc “on” time is critical. Although the pilot arc is designed to scour the surface with the heat generated by the pilot arc to cut through rust and paint, removing as much “extra” contamination from the surface will help improve consumable life. Make sure the work clamp is in good contact with the metal as well, as this will reduce the need for the pilot arc to “hunt” for a return path, and keep down overheating of the work clamp as well.