I stumbled upon a mention of this method on the Pirate 4×4 board and it piqued my interest. The concept is that instead of just retaining the plasma arc fixed and aimed directly downwards during piercing, the nozzle should be oscillated along one axis slightly. This prevents the jet's backwash from flowing upwards and shortening the lifespan of your consumables. Apparently, this technique is also useful for abrasive waterjet cutters due to similar reasons. Some CAM packages, like Sheetcam, offer built-in support for wiggle piercing. Even if your package doesn't, incorporating a wiggle pierce into an existing program with our G-Wizard G-Code Editor software would be rather straightforward.
According to the article, you'd need g-code something like this:
G1 X.06F25.
X-.06
X.06
X-.06
X.06
X-.06
Assuming the torch is at the pierce location in Y and Z, this snippet assumes relative coordinates and wiggles the torch back and forth in X a distance of 120 thousandths either way. The post further suggests you take your normal pierce delay and use a shorter value, about 25% shorter than your normal pierce delay. You'll need enough moves to keep the torch wiggling for that duration of time until the pierce is done. Again, this is easy to arrange with G-Wizard Editor since it tells you the execution time of every code block.
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