Cover Your Amperage, Speed and Standoff.
It's a crude mnemonic and it has stuck with a lot of people for exactly that reason. Those three settings decide your cut quality, your edge squareness, and how long your consumables last. Get them right and mechanized plasma is boringly repeatable. Get one wrong and you'll chase the problem everywhere except where it lives — usually into a box of parts you didn't need to buy.
Here's what each one actually does.
A — Amperage
Amperage is not a dial you turn up for a faster cut. It's a specification the consumables were built around.
Every nozzle has an orifice sized for a particular current. Run more current than the orifice was designed for and the arc pushes against the bore, opens it up, and takes the nozzle with it. The cut goes wide, the edge goes soft, and you replace a part that had plenty of life left in it.
Run less current than the parts are rated for and you get a different problem — a lazy arc that doesn't fully penetrate, more dross, and an electrode that wears unevenly.
The rule: the amperage follows the consumable set, and the consumable set follows the material. Not the other way around. Pick your parts for the plate you're cutting, then run the amperage they're built for.
S — Speed
Speed is where most cut-quality problems actually live, and it's the easiest to diagnose because the plate tells you directly.
Too slow and the arc has time to melt more material than it can blow clear. Molten metal rolls under the plate and freezes there. Low-speed dross is heavy, it comes off in a thick rolled bead, and it's usually the easier of the two to knock off.
Too fast and the arc lags behind the torch. It trails, the kerf angles back, and the material at the bottom doesn't get cleared at all. High-speed dross is thin, hard, and welded on — the kind you grind rather than knock. You'll also see the bevel go the wrong way and the bottom edge round over.
The cut face is your gauge. A trailing arc leaves a visible lag line curving back through the kerf. Read it and adjust in the direction it's telling you.
S — Standoff
Standoff is the distance from the torch to the plate while cutting, and it's the one that quietly destroys parts.
Too low and you risk the shield contacting the plate or molten material. That's how you get double arcing — the arc finding a path through the shield instead of out the nozzle — which is fast and expensive.
Too high and the arc has to stretch. The kerf widens, the top edge rounds off, edge squareness goes, and the arc becomes less stable.
Height control is what keeps this honest. Ohmic sensing and initial height sensing exist because standoff by eye doesn't hold across a warped plate or a long program. If your height control isn't working, or the ohmic contact is dirty, standoff drifts without anyone touching a setting — which is why "nothing changed and the cuts went bad" is so often a height control problem.
Pierce height is its own setting
Worth separating out: pierce height is not the same as cutting standoff, and it's usually higher.
Piercing too low blows molten material straight back up into the nozzle and shield. It's one of the fastest ways to kill a set of consumables, and it's a setting, not a parts problem. If you're seeing splatter damage on the underside of your shields, look here before you look anywhere else.
Why you can't trade one for another
The failure pattern we see most often: something goes wrong with the cut, so the operator adjusts a setting that isn't the cause, and the machine ends up in a place where two wrong settings partially cancel each other out.
It works, sort of, until the material thickness changes or the parts wear a little. Then it stops working, nobody knows why, and the settings are now so far from the chart that getting back is a project.
Change one thing at a time, and change it back if it doesn't help. Slow, but it's the only way to actually know what's happening.
The chart is the starting point
Your machine's cut charts give you a tested combination for a given material, thickness and consumable set. That's where you start, every time.
But a chart is generated in ideal conditions — clean dry air, a fresh torch, flat plate, new consumables. Your shop varies from that, so expect to tune from the chart rather than treating it as final. What the chart gives you is a known-good baseline to tune from, which is worth far more than someone's remembered settings.
And when you do tune, write it down. Settings that live only in one operator's head leave when he does.
What good looks like
A cut that's right has a square face, a fine and consistent lag line, minimal dross that comes off with a knock, and a bottom edge that isn't rounded. When you see that, note every setting that produced it.
That record is worth more than any chart, because it's yours — measured on your machine, your air, your plate. And it becomes the baseline that makes the next problem obvious, in the same way that tracking consumable cost per arc-on hour makes a change in wear rate obvious.
Cover your amperage, speed and standoff. Most of the rest takes care of itself.
Need parts matched to your machine and amperage? Our guided finder walks you from your machine to the complete stack — in assembly order, with current pricing. Find your consumables →
TorchandTip.com sells Thermacut® aftermarket plasma and welding consumables across Canada. Thermacut® is an independent manufacturer. TorchandTip.com is not affiliated with, authorized by, or endorsed by Hypertherm®, ESAB®, Lincoln Electric®, Kjellberg®, or any other original equipment manufacturer. All OEM names, model numbers, and part numbers are used for identification and reference purposes only.
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