Get the most power out of your laser in LightBurn
If 100% power in your software isn’t giving you 100% of the tube, you’re leaving cutting ability on the table. It usually comes down to the max-power / S-value setting.
Applies to
- Process
- Diode & CO₂ lasers running LightBurn / GRBL
- Setting
- Controller $30 (max S-value) ↔ LightBurn S-value max
- Goal
- 100% power = full tube output
Why it matters
LightBurn sends power as an S-value scaled to a maximum. If the controller’s max S-value and LightBurn’s S-value max disagree, your ‘100%’ only asks for a fraction of the real output — so cuts need more passes and engraves look weak.
Matching the two means the full range of the power slider maps onto the full range of the laser, so you get every watt the machine can give.
What good looks like
- Controller max S-value and LightBurn’s S-value max are the same number
- 100% in software visibly drives the laser harder than before
- Min-power/percentage settings behave predictably across the range
How to apply it
- Check your controller’s max S-value ($30 on GRBL is commonly 1000).
- Open Device Settings in LightBurn and set the S-value max to the same number.
- Re-run a small cut test — 100% should now cut in fewer passes.
- Re-dial your material profiles, since the power scale just changed.
Exceptions & tradeoffs
Numbers and menu names vary by controller and firmware — confirm the exact $-setting for your board before changing it.
More power isn’t always better: past clean cut-through you just add char. Use it to reach full range, then tune with a test grid.
Matching the controller max S-value to LightBurn so 100% = full power — Get the MOST POWER out of your Laser by doing THIS in Lightburn! ↗.
Summarized and independently edited by Start Here. Starting values and cautions are our editorial notes, not a quotation from the creator.