LightBurn Settings for Diode Lasers: A Practical Speed and Power Guide
8 min read · Updated October 11, 2026
Diode lasers are the most popular entry point into laser engraving, and LightBurn is the software most diode owners end up using. The hardest part for beginners is not the software itself but knowing what speed and power to use. This guide gives you sensible starting points and, more importantly, a repeatable way to find the perfect settings for your own machine.
Why there is no single "correct" setting
Two diode lasers sold as "10W" can behave very differently. Real optical output, spot size, focus, air assist, and even the moisture in a piece of plywood all change the result. That is why every number in this article is a starting point, not a rule. Always confirm with a quick test on a scrap of the same material before running a real job.
Check these LightBurn basics first
- Device type: most diode lasers run GRBL firmware. Add your laser in the Devices window and choose GRBL.
- Laser mode: make sure GRBL laser mode is on (
$32=1). Without it, the laser pauses at every corner and burns dark spots. - Maximum power value: the
S-value maxin LightBurn's Device Settings must match your controller's$30value (usually 1000). If they don't match, 50% in LightBurn will not be 50% on the machine. - Focus: a perfectly focused beam matters more than any setting. Use the focus tool or spacer that came with your laser every time you change material thickness.
Starting settings by material
The table below assumes a typical 5–10W optical-output diode laser with air assist. Speeds are in mm/min, the unit most GRBL machines use. If your laser is weaker, lower the speed; if it is stronger, raise it.
| Material | Job | Speed (mm/min) | Power | Passes |
|---|---|---|---|---|
| Basswood / birch plywood 3 mm | Engrave (fill) | 3000–6000 | 30–60% | 1 |
| Basswood / birch plywood 3 mm | Cut | 200–400 | 100% | 1–3 |
| Veg-tan leather | Engrave | 3000–5000 | 20–40% | 1 |
| Dark acrylic (cast) | Engrave | 2000–4000 | 40–70% | 1 |
| Anodized aluminium | Mark | 1000–2000 | 80–100% | 1 |
| Slate / stone tiles | Engrave | 2000–3000 | 60–90% | 1 |
| Cardboard | Cut | 600–1200 | 60–90% | 1 |
Diode lasers cannot cut or engrave clear or light-coloured acrylic well: the blue wavelength passes straight through. Stick to dark, opaque acrylic, or use a CO2 laser for clear sheets.
Engraving settings that make the biggest difference
Line interval
Line interval is the distance between engraving lines. Most diode spots are around 0.08–0.15 mm, so a line interval of 0.08–0.1 mm gives a solid fill without wasting time. Too large and you'll see stripes; too small and the wood over-burns.
Overscanning
Enable Overscanning on fill layers. It lets the head reach full speed before it starts burning, which removes the dark edges you often see on the left and right of an engraving.
Bi-directional fill and scan offset
Bi-directional fill engraves in both directions and roughly halves the time. If text looks blurry or doubled, set up Scanning Offset Adjustment in Device Settings to compensate for the small delay at high speed.
Cutting with a diode laser
- Use air assist. It blows away smoke, prevents flare-ups and gives much cleaner edges.
- Several slower passes beat one very slow pass. On 3 mm plywood, two or three passes at a moderate speed usually char less than one crawling pass.
- Lower the focus between passes ("Z step per pass") on thicker material if your machine supports it.
- Order your layers so inner shapes are cut before outer outlines, otherwise parts can drop and shift.
Find your exact settings in five minutes
The fastest way to dial in a new material is LightBurn's built-in Material Test. It burns a grid of squares, each with a different speed and power combination, so you can pick the one that looks best. We wrote a step-by-step guide: How to Run a Material Test in LightBurn.
Once you find a combination you like, save it in LightBurn's Material Library. Next time you work with that material, you load it in one click instead of guessing again.
Safety reminders
- Never leave a running laser unattended, especially when cutting.
- Wear goggles rated for your laser's wavelength (typically 445–455 nm for blue diodes).
- Do not laser PVC, vinyl or anything containing chlorine. It releases toxic, corrosive gas.
- Vent smoke outside or through a proper filter.