If you are using a new electrode and nozzle.....and after use you are refacing them and making them usable again....then that tells me you are not using them to the end of their usable life the first time around!
When the electrode is fully consumed (there are no "tips" on a Hypertherm plasma....nozzle and electrode are the parts) it will have .030" to .040" pit depth on the hafnium emmitter (insert).....if the front of the electrode is faced off to this depth....then the electrode is now too short to make adequate contact with the inner chamber of the nozzle....which will usually result in misfiring, but probably more important...will result in a higher arc voltage if it does fire and transfer to the plate....as the electrode is shorter, making the arc longer. Higher voltage (.040" longer arc will increase the arc voltage by approximately 10 volts)...increases the load on the power supply, shortening the duty cycle, as well as causes arc voltage based height control systems to move the torch closer to the plate....likely causing plate collisions as well as poor cut edge angularity.
When a nozzle orifice is reconditioned...the only choice would be to drill a larger hole (unless somehow the hole is being re-welded with copper, then redrilled to the proper size)....a larger hole will decrease enrgy density of the plasma arc....which will reduce cut speeds and affect cut edge angularity.
My guess is that the time spent reworking the consumables likely is more expensive than figuring out how to get the best life out of new consumables through clean air and proper pierce and cutting techniques.
Jim Colt  |