LightburnModule 2.8~3 min read

Optimization & Job Speed

The Optimization Settings dialog is where Lightburn decides the cut order. Default settings are good; tuning these saves real production time on complex jobs.

Where to find it

Edit → Settings → Optimization Settings. Or click the "Optimization Settings" link in the Laser panel.

The master toggle

Enable Optimization: if off, Lightburn cuts in creation order (whichever shape was drawn first). Always leave this ON unless you have a specific reason.

Order By: the hierarchical sort

Top-level grouping. Combinable, stack multiple criteria.

Layer: process all of layer 1 before any of layer 2. Standard for jobs where layer 1 is "engrave" and layer 2 is "cut", you want all engrave done before cuts free the part.
Group (Cut Group), process each grouped sub-design as a unit before moving to the next.
Individual cut priority: set per shape via Shape Properties (lower number first).

The refinements (the productivity wins)

Cut inner shapes first: for nested shapes (e.g., a hole inside an outline), cut the hole before the perimeter. Otherwise the part falls free before you cut the inside. 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: try to keep the head moving in similar directions. Small gain on most jobs.
Choose best starting point: picks the entry point on each closed shape that minimizes travel from the previous cut. Smooth tiny win.
Choose corners, if possible: start cuts at a corner rather than mid-side. The "join seam" hides better at a corner. Subtle quality win.
Remove Overlapping Lines (with distance tolerance), when imported designs have duplicate or near-duplicate paths, this strips them. Fixes the "why is this engrave running twice" problem on imported SVGs.

Galvo-specific job speed hacks

Galvo jobs aren't limited by gantry travel, they're limited by hatch density and total fill area. The biggest wins:

Flood Fill ON (in Fill mode settings), drastically reduces blank-space jumps between disconnected fill regions. Always on.
Bi-directional ON: galvo sweeps both directions. Default. Turn off only for ultra-precision needs.
Increase Jump Speed: galvo mirrors travel between marks at this speed. Faster jump = faster overall job, no quality cost.
Cleanup pass freq tuning: for relief coins, every-8-passes cleanup is faster than every-2-passes with comparable quality.

Gantry-specific job speed hacks

Hide Backlash: DSP-flavored builds. Reduces overshoot at high speed; some quality cost on very fine detail. Worth testing.
Fast Whitespace Scan: GCode lasers only. Speeds up traversal across blank areas.
Use higher Cut Speed for short cuts: short cuts don't reach max speed under typical acceleration. Bumping cut speed helps in short-segment jobs more than long ones.

Reading the Preview to spot waste

Open Preview (Alt+P) and watch the simulation:

Lots of red lines (traversals)? Optimization isn't doing much. Check Reduce travel moves is on, and that you don't have shapes scattered across opposite ends of the bed.
Cut paths repeating? You probably have duplicate shapes from a sloppy import. Run Tools → Delete Duplicates or enable Remove Overlapping Lines.
Inside cuts after outside? Optimization is off, or "Cut inner shapes first" is unchecked.

Where the settings save

Optimization settings are stored per project file (.lbrn). Open a different file and you might be running a different optimization preset. Check before every production run.

A 10-minute audit that pays back hours

Open your most-run job. Alt+P. Note the time. Open Optimization Settings, try toggling on "Reduce travel moves," "Reduce direction changes," and "Choose best starting point." Re-preview. If the time dropped 10%+, save the project. You just bought back time on every future run.

Verified against LightBurn 2.x. Source: LightBurn official docs. OptimizationSettings, Preview, Job Time Optimization collection.