I am kind of new to the world of plasma but not so much to gantry type CNC machines.

I am converting one of my mills into a plasma cutter and need to find a solution for the THC. I am still researching/shopping for the best option. I plan on using Mach3 as I already know the software and have the license.

What I need clarification on is THC. From what I understand is that a THC system continually measures the arc current at the touch while cutting and will increase/decrease the touch height using the z axis to maintain a consistent cutting distance between the torch and the work piece. Is this correct?