How long should consumables last on my Powermax air plasma?
It’s hard to give an exact (or even in-exact) number as so many factors impact consumable life—operator experience, type and age of the torch, material type and thickness, air quality, etc. However, if the operator understands good piercing and edge starting techniques to keep molten metal from blowing back onto the torch nozzle (or tip if a non-Hypertherm system) then consumable life can be extremely good.
The biggest problem with most plasma torches occurs when hand cutting with an exposed (unshielded) nozzle. Ideally, you need to hold a standoff with an unshielded setup at all amperages greater than 30 amps or so. If the nozzle touches the plate during a cut it creates a current path between the negative electrode, nozzle, and positive plate. This causes a double arc between the electrode and nozzle, and the nozzle and plate, which damages the nozzle orifice. When the orifice gets a little damaged, poor angularity is the first thing you’ll notice, followed by more double arcs and more damage. Eventually you’ll notice slower cut speeds and heavy dross, at which point you’ll likely change your nozzle.
Some people use a standoff device to hold the torch up off the metal. Unfortunately, molten metal can still blowback during piercing, once again creating a current path from the nozzle to the plate and leading to double arcing. If you have used a hand held torch with an exposed nozzle at more than 30 amps while drag cutting, you’ve likely felt the torch “sticking” to the plate. This is a result of double arcing.
One way around this problem is through the use of shielded torch technology, invented and patented by Hypertherm in the 80’s. The shield works to electrically isolate the nozzle from the plate to totally eliminate double arcing. Hypertherm shielded torches drag cut at up to 200 amps with no friction or double arcing for a dramatic improvement in consumable life and cut quality.
In the 30 or so years since Hypertherm introduced shielded torch technology, engineers have made enormous strides in the life of these consumables. For example, our Duramax torches which come standard with nearly all new Powermax systems and as a retrofit torch for most older Hypertherm systems use the shield for more than just nozzle isolation. The shield and nozzle for these torches use patented technology called Conical Flow to inject greater air flow around the perimeter of the arc. This increases the energy density of the arc and provides better cooling to the nozzle. The result is no sticking, no double arcing, faster cut speeds, thicker piercing capability, and dramatically longer nozzle life.
So, assuming you are using a Duramax torch with the latest consumable technology, then I would expect you to cut hundreds of feet of metal. In addition, you should be able to make between 600 and 1,200 pierces, after which time you would need to replace your electrode. Your remaining consumables would likely continue to work just fine. Put another way, you should be able to get between 2 and 4 full days of actual arc-on time before needing to replace any of your consumables.