You start a cut on the xTool P3, the machine finishes… and the material hasn’t fully separated: the piece is still connected at some point or it hasn’t gone all the way through. The reflex is to increase the power or pass twice. Almost always there’s a better and less aggressive answer: it’s a matter of focus. And if the problem goes further, it’s beam alignment.
This guide gathers and adapts into Spanish two sections from xTool’s documentation for the P3: cutting thick materials and optical path calibration.
Focus first, not power
A laser cuts better when the focus point is in the right place inside the material, not on its surface. With thick materials, the default focus falls short and the beam loses energy before going through. Before adjusting power and speed, try these two P3 tools:
- The "Lower the Focus" function. It moves the focus point downward, inside the material’s thickness, so the lower part of the cut also receives enough energy. It’s the first resource for thick materials.
- The "L" Focus Lens. It’s a lens specifically designed for cutting thick material: it has a longer focal length and a longer, narrower beam depth, which helps penetrate thicknesses that the standard lens can’t cut cleanly.
xTool has detailed setup guides for both—how to activate "Lower the Focus" and how to install and calibrate the L lens; we link their support center at the end for step-by-step instructions with your firmware.
And check the air
Before assuming it’s power, remember that insufficient airflow also causes incomplete cuts and burnt edges: the smoke doesn’t clear and the beam hits dirty. If besides not cutting through you get yellow edges, start there—we cover it in the guide on yellowing cuts—because air and focus are the two usual suspects for a cut that doesn’t finish.
When the problem is the beam: calibrate the optical path
If the cut is generally incomplete not just on thick material, and especially if you notice any of these symptoms, the issue is no longer focus but beam alignment (optical path calibration):
- Incomplete cuts on materials it used to cut without problem.
- Engraving lines come out thicker than usual (a sign the beam isn’t properly centered).
- You just replaced mirrors or the laser tube.
In a CO₂ laser like the P3, the beam bounces off several mirrors before reaching the lens. If those mirrors aren’t perfectly aligned, some energy is lost along the way and the machine stops performing at full power, even if the setting says 100%. Optical path calibration returns the beam to its correct path.
It’s a delicate procedure with precise steps: xTool publishes an official video guide and step-by-step guide to do it safely. Don’t try to improve it "by eye": follow the brand’s procedure (linked below). If you just changed mirrors or the tube, this calibration isn’t optional—it’s the missing step to get the machine cutting like before.
Frequently Asked Questions
Should I increase power or lower the focus?
Try lowering the focus first (and using the L lens on thick material). Increasing power aggressively burns the material more and wears out the tube faster, and often that wasn’t the problem. Correct focus cuts cleaner with less power.
When to use the L lens and when the standard one?
The standard lens works well for most fine work and medium thicknesses. The L lens is for when you’re cutting clearly thick material and the standard lens can’t reach. It’s not “better” overall: it’s specific for thickness.
I changed the tube and now it cuts worse. Why?
Almost certainly alignment. When you change the tube or mirrors, the beam shifts and you need to recalibrate the optical path. It’s expected; follow the official calibration guide and you’ll recover performance.
Written by Noemi and Javi, from Picasita. We’ve been using an xTool P3 in production since October 2025; we are xTool affiliates. This guide adapts the brand’s official documentation; the original is in their support center. More tutorials and solutions.
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