Torch don't stay down

has anyone had this problem ?
the torch start good but then the THC raises the torch as it start cutting,
i on a Crossfire PRO using fire control and a Powermax 45 XP plasma. i’ve made thousands of cuts with no problems. i tried another G-code and also a straight cut in fire control with all having the same problem.
voltage test all tested Good. 127.2 volts

Help anyone!


here are some basic things to check…even though you have had thousands of cute we all somtimes forget the most basic things.

  • clamp to material not slats
  • laptop not plugged in to charger and/or using ground isolation plug
  • check all your wires and make sure they are not overlapping
  • have you recently moved your plasma cutter or table and they are too close together
  • clean contacts on the THC…they get dirty from spashback and can give false readings

This sounds basic… but happened to me. I thought I entered 0.06 for cut height in sheetcam… accidentally had 0.6… didn’t catch it and torch would initial sense, start to move up to 0.6 while it starts to proceed with cut… LOOSES arc at height after pilot kicks out.

Double check your z height code

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Nevermind, I missed the part that it’s doing in straight cut test. Are you running auto volt in the thc settings?

Fouled consumables can have this effect.

Are you running thin materials?

Thanks guys.
i believe it was dirty contacts

sometimes I am right…hehehehehehe

Ok, dumb question… what contacts did you clean because I am having the same exact issue.

It’s not really contacts. The only contacts are on the IHS switch and that is either an open or closed thing, so it either works or it doesn’t. The thing that they are cleaning is the wheels that ride on the rods in the Z-axis. There is a plastic isolator that is supposed to prevent a ground loop from occurring between the IHS wiring and the frame of the machine. Metal dust can get in there and complete the loop, causing phantom voltage to be reported to the THC. Blowing it out with compressed air seems to help.