All good questions!
Plasma consumable life is dependent on a lot of factors:
- Average duration (in seconds) of each cut cycle.
- Number of pierces
- Air purity (moisture and oil)
- Pierce technique
- height control accuracy
- Material thickness
So.....if your average duration is long, expect less total pierces, but more lineal cut length out of a set of consumables. If you have a lot of starts with short cut cycle durations....expect more starts and less lineal cut length from a consumable set.
If you are piercing within the Hypertherm piercing limits, and using the pierce delay time and pierce height from the Hypertherm manual....you will get maximum life from your consumables. One pierce too close, or with inadequate pierce delay...and you may have ruined a nozzle.
Moisture always pops up as the prevalent problem this time of year in North America....due to hot weather and high humidity. Our tech service department is always swamped with calls regarding short consumables life during high humidity weather.....with many callers insisting that there must be a problem with the torch, or must be a bad board in the power supply. Moist air causes extremely short consumable life and poor cut quality.
Assuming everything is being done by the book, and the air is clean and dry....then I normally expect approximately 400 to 600 starts when cutting 1/4" material parts.....with an average cut duration in the 20 second range. Some cuts (holes) are just a few seconds, the perimeter cuts may be more than 20 seconds....but if I average the cut duration.....roughly 400 to 600 starts with this type of cutting, and roughly 5000 inches or so of linear inches cut per electrode and nozzle change....with a Powermax45.
On thinner material and lower power levels, I can normally get double that life...both in the number of starts as well as the lineal inches cut per nozzle and electrode.
I am picky about cut quality and edge angularity....and the above numbers do not indicate when the consumables fail to cut.....but when the cut quality in terms of edge angularity gets outside of my expectations. If you lower your standards....you can cut with a Powermax 45 beyond my expectations of life.
The Hypertherm HPRxd industrial plasma systems produce dramatically longer life due to the gas flow system, the liquid cooled torches, as well as the microprocessor controlled output power. It is fairly normal with these systems to get 1600 or more starts on 1/2" material (cutting at 120 ipm or more) and 2 miles (126,720 inches) of cut before changing consumables.
Often when cut quality starts to suffer....I inspect the consumables, clean the shield and change only the nozzle. Learning what to look for is available in the Hypertherm manuals....even better, check out the free training from Hypertherm for consumables optimization....this may give a better understanding as well....here is a link: