Just to clarify, for those of you who are wondering what the difference is between a pilot arc cutter and a regular one (as I was). This is the best description I could find.
"A plasma torch with a pilot arc will fire a low power plasma arc in the air....this is a DC arc that goes from the torch electrode to the torch nozzle...and the force of the air blows the arc out through the nozzle (tip) orifice. The function? The pilot arc is designed to improve the ability of the plasma arc to transfer to the materials that needs to be cut......as the pilot arc approaches the plate, it burns through any surface issues (paint, rust, masking materials) and quickly transfers the arc....which electronically senses that current is now flowing through the work ground cable...and amperage ramps up (you will see the arc get more intense.
Older technology plasmas, and todays industrial mechanized plasma systems....use a pilot arc that is started with a high voltage, high frequency discharge between the nozzle and electrode to get the cutting air ionized. Newer technology air plasma systems use a "blowback start" ( a moving, spring loaded electrode in the torch) to ionize air, and are able to start a pilot arc without the use of high frequency.
Non Pilot arc torches have to allow electrical contact with the plate to be cut....by physically touching the plate (like scratch starting a TIG). These plasma torches use a high voltage, high frequency discharge that arcs between the torch nozzle (tip) and the plate that ionizes the air in this area, and gets the main arc transferred to the plate.
Pros and Cons?
Blowback style (non high frequency start) torches will transfer an arc to the plate from a fair distance (my Hypertherm Powermax45 will transfer from 1/4" away from the plate). This long transfer distance allows for best plate piercing capability in a mechanized application...by allowing the torch to stay back at a good pierce height which allows the pierce spatter from hitting the torch nozzle orifice....which cause nozzle wear and poor cut quality. The pilot arc also allows for rapid starts on rusty, scaly, or painted materials. Firing the pilot arc in the air will cause nozzle orifice erosion....and should not be done often. I once vivited a user of Hypertherm hand held torches that was doing some cutting inside large storage tanks....it was dark in there and he was using the torch pilot arc as a flashlight. His complaint...short consumable life......we solved his problem by buying him a flashlight.
Non pilot arc torches work well on clean metals, although having to touch start a torch is extremely tough on the torch nozzle (tip), as the arc starts with the nozzle in contact with the plate...and molten metal has no where to go except right back on the nozzle orifice. Once the orifice is no longer perfectly round...cut speeds slow down and cut edge angularity gets worse. Generally....a non pilot torch will not work on a cnc machine...as it is difficult to get the torch to scratch the surface to get the arc started....and, many cnc machines will be adversely affected by the high frequency required to start the torch. It is less expensive to manufacture a non pilot arc plasma system.....and that is the primary reason they are available."