How to score a line on 3mm poplar ply without cutting all way through. Im dropping the power right down and upping the speed but still cuts through
Welcome
Are you controlling the laser directly with Lightburn?
Explain a bit more of your workflow.
There are 2 modes, cutting and engraving. The only difference is how much power at what speed is used for the task. (very simplified)
Find out what your minimum power is, your laser will shoot and you have a starting point. If we assume you have a CO2 laser with Ruida controller, the speeds for engraving will be between 100 mm/s and 300 mm/s - with up to 20% power for example, and for cutting, up to 50mm/s for thin poplar plywood at 15-40% power. But, it is very dependent on your laser - which we do not know.
If you are new to all this, it is highly recommended that you start with the material tests that are already available in LightBurn, it gives you more feel for your machine.
Focus depth will also affect the amount of ablation occuring. Sharp focus will concentrate all the energy in a tiny spot, cutting deeper. Fuzzy focus will spread the energy over a greater area (also makes your line wider than sharp focus) - resulting in a mark on the wood rather than a hole all the way through.