Layer Settings for CO2

Every Lightburn layer parameter you'll touch on a CO2 / Ruida machine, what it does, when to change it. The galvo-specific Q-Pulse and TC delays don't apply here, gantry has its own knobs instead.

Shared settings: Common tab

Field	Unit	What it does
Speed	mm/s	Maximum head velocity. Cut speed is what you tune most often.
Max Power	%	Peak laser output during the cut/engrave.
Min Power	%	Lower bound. Critical for ramped cuts and Grayscale image mode. Power ramps from Min → Max as the head accelerates to full speed.
Number of Passes	integer	Repeat the layer N times. Used for thick cuts.
Air Assist	toggle	Enables the air solenoid for this layer. Tune pressure separately at the compressor.
Output	toggle	If off, layer ignored on Run / Preview / Save.

Line mode (cuts and scores)

Kerf Offset	Compensates for beam width. Positive = path expands outward (parts come out larger). Negative = path shrinks (cutouts come out larger). Typical for acrylic: 0.1-0.2mm; wood: 0.15-0.3mm.
Tabs / Bridges	Leave small uncut sections so parts stay attached to scrap until you remove them. Set tab count + length per tab.
Perforation Mode	Cut a dashed line instead of solid. For paper craft fold lines.
Overcut (Advanced)	Extends the cut past the closing point of a closed shape, burns away the join seam so closed shapes drop free cleanly. 0.1-0.5mm typical.
Lead-In / Lead-Out (Advanced)	Adds entry/exit cuts OUTSIDE the path. Useful when the entry burn mark would mar a finished part edge.
Z Step per Pass (Advanced)	Drops Z by this amount each pass. Critical for cutting thick stock, keeps focus on the working depth.
Cut Through	Final-pass logic that finishes any unsevered shapes. Helps with thick acrylic.
Constant Power Mode	For some controllers, disables power ramping; runs at Max Power throughout. Useful for some thick cuts.

Fill mode (engraving / rastering)

Line Interval / Lines per Inch	Distance between hatch lines. Smaller = denser fill. Typical for engraving: 0.06-0.10mm (254-423 LPI).
Scan Angle	Direction of hatch lines. 0° = horizontal. Rotate slightly per pass to mask scan-line artifacts.
Cross-Hatch	Run a second pass at +90° to scan angle. Doubles fill density. Used for solid blacks, deep engraves.
Bi-directional	Default ON. Engraves both directions of head travel; faster.
Overscanning	Extends scan past edges to compensate for acceleration ramp. Default 2.5%-5%. Higher = cleaner edges, slightly more time. DSP / Ruida applies automatically.

Image mode (photos and grayscale)

See dedicated Image Modes module for full coverage. Quick reference:

• Threshold: pure black/white cutoff.
• Dither / Stucki / Jarvis / Atkinson / Newsprint / Halftone: different patterns simulating gray.
• Grayscale: modulates Power Min ↔ Power Max per pixel. Used for tonal engraving on wood, slate, leather.
• Pass-Through: sends image as-is without internal resampling.
• 3D Sliced is galvo-only; not available on CO2.

Common Ruida-specific settings

• Default Speed/Power: controller has its own defaults that activate when you push File from Ruida memory directly. Lightburn overrides when running live. Verify the controller defaults match your typical work, or jobs run from memory will use stale settings.
• Backlash: Ruida has a backlash compensation parameter accessible in machine settings. Don't tune unless you have visible artifacts.

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