Can I turn off the THC on certain jobs?

I have an Avid 4848 with a Hypertherm 45XP. I found when cutting 1/4’ plate with some close cuts or fine detail, the torch tends to drive down and hit the plate causing the cut to be incomplete and ruin the part. Is there a way I can turn of the THC and have it cut at the height I set?

I too am using a Hypertherm 45XP and the THC on my machine.

I cannot answer for Mach-4 as I am not currently using it. I can answer for the AVIDcnc setup in Mach-3 which I am using and the answer most definitely is yes, it can be turned off there.

Of course, one has to make sure that the surface of the metal is reasonably level over the length of a cut.

A great example of a case where one might want to do that comes up when cutting perforated steel where there might be 1/4in or 3/8in (or bigger) holes everywhere.

Speaking of, , I cut perforated stainless steel a small number of times a year (2/3ish). Just this last week I was cutting material with 1/8in perforations (image below) and the plasma cutter moves across those repeated interruptions with the THC turned “ON” without to much problem. I suspect if one gets to 1/4in or 3/8in perforations it might be a different story.

Can you share a photo of the area you were trying to cut where the failure happens? Also, what material was being cut (Carbon Steel, Stainless, Aluminum, etc), what consumables were installed in the torch (standard or fine cut) what voltage was set for the cut and lastly, what travel speed was programmed?

I ask the above questions as I cut a reasonable amount of 1/4in and tons and tons of 3/16in material and I am not having similar experiences. I do understand that if one cuts say “a linear move” and then back-tracks over it for a good amount of length, then yes the THC can dive into a part. But just running across an existing perpendicular cut in 1/4in material should not cause this to happen. Hence the request for the photo and the questions above to help understand what is going on and if there is anything that can be corrected.


That is an M code and I forget which one it is. Will look it up when I have more time.

M63P4 (***THC Inhibited, AD2***)

Just issue the above after the height is set for the cut and then when that op is finished;

M62P4 (+++THC Allowed, AD2+++)

Clarification; I believe those are for Mach4 only. Could be wrong though.

I am cutting mild steel, using the standard tips/consumables that come with plasma. I will get you the consumable kit number when I get home. I will also get you a picture. I am running MACH 4 and I don’t know how to turn off the THC in that program.

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You turn it off in CAM, not Mach4. Maybe I wasn’t clear, I apologize.

This is instruction for SheetCam BUT use the codes I posted below that AvidCNC provided with their post processor + tools install;

Thank you sir. I have a great deal to learn. I will have to watch the video several times to get comfortable with it. I appreciate you taking to time to respond.

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Yep, takes me a few times too :grin: