Ok, I’m really confused with this one, and I can’t seam to find any information about it on the net. I’m designing a plasma table, 5’x8’, but I haven’t the slightest clue what triggers the torch on/off when it needs to be on or off? I’ve seen pictures with the trigger wrapped so its constantly on, but I don’t know if the plasma cutter’s power is somehow hooked up to the CNC driver board or what? Or maybe I could hook the trigger up to some kind of actuator?? I’m not sure on this one. Any help would be greatly appreciated! Thanks:confused:

What are you going to run as a control? Normal way to trigger torch on/off is just like you do it for a router spindle: GCode M03 triggers a relay, M05 turns it off. Relay contacts are put in parallel with torch switch so Either will trigger the torch. Your electronics (breakout board or THC) should have provisions to turn the torch on/off via an isolated switch.

The insertion of M03 and M05 at the right time for plasma into g-Code is a function of the CAM software (POST). It's part of the toolpath definitions along with Lead-in's, pierce height, pierce delay, cut height and feedrates for a given material and tip combination.

Look at SheetCAM as a CAM program for 2D (shape cutting) or 2.5D (pocket milling). It's inexpensive and has lots of features you will need for plasma cutting. It's not just as simple as turning on the torch and cutting steel. Read some of the threads about the tip clogging problems others are having and read and understand what a Torch Height Controller does and if you need one.

It's actually more complex to get good cuts with plasma than with a router or milling machine.

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There is a relay that is triggered by your software, it will use a "M" code to turn it on/ off.
Here is a board that has the relay on it. It is attached to the wires that normally go to your trigger.

http://cgi.ebay.com/CNC-PLASMA-ROUTER-RELAY-CONTROL4-STEPPER-MOTOR-SYSTEMS_W0QQitemZ330139754390QQihZ014QQcategoryZ71394QQrdZ1QQcmdZViewItem