CO2 Optimization & Job Speed

CO2 jobs are gantry-bound, so traversal time matters MORE than on a galvo. Optimization Settings can shave 15-30% off complex jobs. Here's what to tune.

Open the Optimization Settings dialog

Edit → Settings → Optimization Settings. Or click "Optimization Settings" in the Laser panel. Settings save per-project.

Master toggle

Enable Optimization: if off, Lightburn cuts in creation order. Always leave this ON.

Order By: the hierarchical sort

• Layer: process all of layer 1 (e.g., engrave) before any of layer 2 (e.g., cut). Standard for jobs where the part needs to stay anchored during the engrave.
• Group: process each grouped sub-design as a unit. Useful for multi-part fixtures.
• Individual cut priority: set per-shape via Shape Properties (lower number first).

The refinements (real wins)

• Cut inner shapes first: for nested shapes (hole inside outline), cut the hole BEFORE the perimeter. Otherwise the part falls free before the inner cut runs. Always on for cutting jobs.
• Reduce travel moves: sorts cuts to minimize jump distance. Biggest win on complex jobs with many small disconnected shapes.
• Reduce direction changes: keeps the head moving in similar directions. Small gain on most jobs but reduces wear.
• Choose best starting point: picks the entry point on each closed shape that minimizes travel from the previous cut.
• Choose corners, if possible: start cuts at a corner rather than mid-side. Hides the join seam.
• Remove Overlapping Lines (with distance tolerance), strips duplicate paths from imported designs.
• Hide Backlash: DSP-flavored builds. Reduces overshoot at high speed; tiny quality cost on very fine detail. Worth testing.
• Fast Whitespace Scan: GCode lasers only. Speeds up traversal across blank areas.

Layer ordering practices

1. Engrave layers FIRST. If the part is cut free before the engrave runs, the engrave wobbles or misses entirely.
2. Inner cuts BEFORE outer cuts. Holes before perimeter.
3. Score lines BEFORE cuts. Avoid scoring an already-cut piece that's loose on the bed.
4. Slowest cut LAST if multi-pass. Final pass at slowest speed for cleanest finish.

Speed gains worth chasing

Optimization	Typical time savings
Reduce travel moves (was off)	10-25%
Cut inner shapes first (was off)	2-5%
Choose best starting point	3-7%
Hide Backlash on production	5-12%
Increase Jump Speed (Ruida)	5-10%
Remove Overlapping Lines (imported SVG)	10-50% (depends on duplicates)

Reading the Preview to spot waste

• Open Preview (Alt+P). Black = cut/engrave. Red = traversal.
• Lots of red? Optimization isn't doing much. Check that "Reduce travel moves" is on.
• Repeating cuts? Duplicate shapes from a sloppy import. Run Tools → Delete Duplicates or enable Remove Overlapping Lines.
• Inside cuts after outside? Optimization off, or "Cut inner shapes first" unchecked.

The 10-minute audit

1. Open your most-run production file.
2. Note the Preview time estimate.
3. Open Optimization Settings. Toggle on Reduce travel moves, Reduce direction changes, Choose best starting point.
4. Re-Preview. If time dropped 10%+, save the project.
5. Buys back time on every future run of that file.

Verified against LightBurn 2.x. UI specifics may shift in future versions; verify against your installed version.