Laser-Cut Wood Files: Bridges, Detail Limits, Safe Settings

The two failure modes on wood are char and falling pieces. Char shows up on tight inner corners, thin webs, and any feature smaller than the kerf can resolve cleanly. Falling pieces happen when a path encloses an island that the bed can't catch — letters with counters (a, b, d, e, o, p, q, R) are the classic culprits. A pour of glue won't save a sign whose centers landed on the floor of the cabinet.

For 3 mm plywood on a 40–60 W CO2 laser, start at ~10 mm/s at 80% power for cut and ~150 mm/s at 25% power for engrave. Lazrit's wood profile enforces a 1 mm minimum detail and 2 mm minimum bridge — both can be raised for harder stocks or lower-power machines, but going lower will silently produce files that look fine on screen and fail on the bed.

Upload a raster or SVG → Lazrit traces the outline, runs topology validation, and flags any islands without a bridge. The auto-bridge engine adds the shortest, least visible connectors that survive the cut. You can drag, delete, or add bridges by hand before exporting. The final SVG has cut paths on one layer and any engrave paths on another, ready for LightBurn.

Plywood: watch for voids in the inner plies — they show up as scorched patches. Hardwood: dense and slow-cutting; bump power, not speed. MDF: see the dedicated MDF page — the binder smokes hard and shows char much more than birch ply.