pm85 losing cut and skipping cut

[jackleg007]

hi jim...im running a powermax 85 on a fastcut table.everything worked fine for over a year,now a problem has developed that i can not track down.the plasma loses its arc,or misses a cut completely every 5 or 6 cuts or so....if i rerun the program it will miss at completely random times,so i have ruled out a problem with the cut files....i have also gotten a low gas pressure error on occasion,i have completely checked the air system one componenet at a time and it is fine....this cutter has never had anything but absolutely clean,dry air ever ,so i tend to rule out the air system as well.

haven't had the low gas error for awhile now,but at times it seems like the cutter is struggling with the air,like a sticking air solenoid or or valve,or having trouble firing the arc or something.grounds have been checked and confirmed good.

now i am down to the cutter,computer,or table control box......i re-installed all software,checked all connections,etc,and all seems good.we did have some strange power bumps a while back that caused me to re-install all software at that time as well.problems developed kinda around the same time,so could be a computer thing

anyhow,i am stuck as to narrow it down without packing it up and sending it to fastcut for testing....they are 2000 miles away and i would like to avoid the downtime and shipping issues.

any ideas how to go about testing the cutter to see if a problem exists with it,or have there been any other common issues that might make the pm85 behave in this fashion....that you know of?any advice would be greatly appreciated,thanks

[jimcolt]

In over 90% of the cases with similar symptoms...you will be experiencing some air starvation either at the air inlet or internally.


First, install a presure gauge right at the air inlet, after every hose, filter, fitting etc. With the torch idle, chack your air pressure back near your compressor, and also at this new gauge. They should read the same (or within a few pounds of pressure). Next, trigger the torch briefly...the air will flow for 10 seconds or so....again read both gauges. You will see a pressure drop...the one at the compressor will be high, the one at the inlet to the plasma will be lower. The pressure drop is caused by restrictions in your plumbing between the compressor and the plasma. The hose could be too small in diameter (needs to be at least .375 ID) or too long (no more than 50'). If you have filters they could be getting clogged or saturated. You could have some debris or rust buildup in a fitting. There could be icing (often reported during colder months)

powermaxpressuregauge 001.JPG

If the pressure entering the plasma is ever lower than 90 psi...your cut quality will be affected. Could be that at different points on your compressor cycle the inlet is dropping too low (way low and you will get a low pressure fault), and is causing the arc to lose power...meaning it will not cut all the way through. Make sure also that your air control setting is set in Automatic mode, this is covered in your manual. It may have accidentally been reset to manual, which means you may have the incorrect cut pressure.

The onboard regulator filter drain could also be partially plugged.

Best regards, Jim Colt Hypertherm

[jackleg007]

thanks for the reply...i will try chhecking the air system with pressure gauges as you suggest.i know the piping is suffucient as this has bee an operating plasma system for a year and a half,but will try the gauges to determine if there is pressure drops along the air path.upon inspecting the system,everything appears fine but it definitely seems to be air related in some fashion...plasma cutter threw a couple of random codes over the last couple of days.i will get back to you with what they were.

i was thinking of sending you a video of the plasma cutter in action to better explain whats happening.

will continue with the checking of the air system as you suggest

[jackleg007]

hey jim...checked the air pressure at the cutter and found the pressure never drops below 95 psi.was a good method for narrowing down my search....it appears to the plasma cutter,now to determine if there is anything else i can do before i have to send it away.new consumables did not correct the problem.is there any way to check the torchlead and torch body?

[jimcolt]

Does this skipping only occur on certain thicknesses of material...or with certain consumables (FineCut on 10 gauge, 65 amp shielded on 1/2" act the same?). Give me some more details regarding when it occurs and under what conditions..

Jim Colt

[jackleg007]

doesnt seem to matter what thickness or consumables.....conditions are completely random.....sure does behave like an air problem as far as i can tell.still get the low gas pressure error occasionally,and the gauge at the cutter shows 130 psi.....im thinking that pretty much narrows it down to bad sensor or selonoid valve or somethingvery early in the air path...of course i could be completely of my rocker...but seems like a good guess:)