Are you looking for the CNC controller to run the sterpper/servomotors, or do you want an auto torch height control? Both are available for very reasonable sums. A most popular CNC controller is the Mach 3 series. And others on this site can recomment a ready made THC. Note that you will need the table and carriage, Z axis mechanism, motors and gearboxes and gear rack, stepper or servo drivers, interface cards, and plasma unit to accomplish this.
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