If your plasma torch is either not firing when it should or if the torch is remaining on when it shouldn’t, your 2T/4T setting might be incorrect. In this post I will explain the difference between 2T/4T mode, and show you how to tell if your plasma cutter is set appropriately.
What is 2T/4T?
In 2-Touch mode, the first touch of the trigger engages the torch at the set amperage, then the second touch disengages the torch. 2T mode is the required setting for most CNC machines, including the CrossFire. CNC machines do not need to taper up to and off of the ideal amperage because they provide uniform torch standoff distance and feed rate. CNC machines simply need to be able to turn the torch on, and then turn it back off.
In 4-Touch mode, the first touch of the trigger engages a low-amperage start, the second touch ramps up the cutter to the set amperage, the third touch ramps down the cutter to a low-amperage end, then the fourth touch disengages the torch. 4T mode is the preferred setting when cutting by hand for most people because it allows more control over the plasma arc without shutting the torch off. However, if a plasma cutter is set to 4T mode when used with a CNC machine, the CNC machine will still think that it is set to 2T mode. This will cause the CNC machine to use the cutter in low-amperage for the first cut, full-amperage when it is supposed to disengage and move to a new location, low-amperage again when doing the second cut, etc.
How do I locate the 2T/4T switch?
The location and labeling of the 2T/4T switch varies between plasma cutter manufacturers and models, but in most cases it is clearly labeled on the front of the machine. If you are unsure if your plasma cutter utilizes a 2T/4T switch, you can consult your user manual or contact your manufacturer for more details.
If you purchased the Razorweld 45 from Langmuir Systems, the 2T/4T switch is the leftmost red triangle on the front panel. The top light indicates that it is set to 2T mode, and the bottom light indicates that it is set to 4T mode. For visual assistance, refer to this image: