Torch rising during cut

As I’m cutting the outside profile of my sign, the torch rises up, far enough it’s not even making a mark on the metal.

It’s been working perfectly for the past 8 months. I do have the thc and have re run the tests.

What am I missing here?

Ground clamp is attached directly to the material, I have an air water separator (and the water has never been an issue)

I use sheet cam

To finish the piece re cut the outside but turned off the thc and it worked.


Is it a new program or one you’ve cut before?

Is your z-axis running smoothly? If you raise it up and down with the page up and page down keys at 50ipm (in firecontrol), is it smooth?

How long of a program is this?

Not long, it’s a 8” sponge bob :disguised_face:.

I loaded up another program I have cut recently and it worked.

I wonder if it was something to do with the programming of g code in sheet cam.

I’ll play with it some more today.

I think so. I why I asked if its a new program.

Check the your cut height decimal place in the program. I’ve seen a too high height cause this issue before.

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Unless you programmed it with different operations for the inside and outside cuts, there is nothing in Sheetcam that will tell the torch to rise like that. If you created different operations for inside and outside and used a different tool for each, then its possible that your cut height is wrong in one of the tools.

Otherwise, this is a problem that is occurring between the control box and Firecontrol. I’ve never heard of it before, but Cameron from Langmuir commented on a similar Facebook post about the IHS wires being loose. He said that loose wires could cause the IHS system to report that the switch is open and the torch will rise .060" each time it happens, because the system thinks the torch is touching the metal. Watch the screen during the cut and see if the IHS light goes on and off when it rises.

Just a thought but depends if the inside cut are short enough, it would not give the THC to rise badly during that cut. but during the outside cut which is longer this gives it enough time to react poorly to the incorrect height.

Good point I had that issue early on where the ring connector from the IHS would become loose where it was screwed down on the Z axis.

This is something that was new to me, but it makes sense. Apparently, if it happens during the cut, it doesn’t throw an error but raises the torch to prevent a collision. If it happens during the probing sequence, it throws an error and stops the program.


I just had my THC not work for some reason. When it was cutting, it just decided not to lower on a section of plate that was slightly lower and did not cut all the way through and had no codes. Have you seen this happen before?

Sounds like your z-axis might be binding up. Without cutting just use the page up and page down keys on your keyboard to raise and lower the z axis at about 50- 100 inches per minute see if there’s any sticking or binding happening you may have to make some adjustments to the travel.

@Brokehusband welcome to The Forum

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Is it possible that the Z axis couldn’t go any lower because it was already as low as it could go without triggering the IHS switch? If it lowers enough to trigger the switch, Firecontrol will raise the torch by .060" as a safety measure.


Thank you for the suggestion. I will give this a try tomorrow I greatly appreciate the help.