When running text or primary shapes in plain Fill mode, the marked text appears, but there is also unintended background burning across the entire horizontal scan band of the text block. The artifact appears as a faint rectangular haze or overburn outside the actual character strokes. The issue does not appear to be random. It appears tied to raster/fill behavior and scan-line overlap.
Observed Behavior
- Plain Fill mode produces unintended overburn/haze across the scanned region surrounding the text.
- The text itself still marks, but the surrounding scan field is also lightly affected.
- In a separate test using two adjacent ovals, areas sharing horizontal scan regions showed additional overburn.
- This suggests the problem is related to horizontal scan-line handling, not just a specific text object.
System
- Laser: Monport 10W UV galvo laser
- Software: LightBurn Pro 2.0.05
Initial Working Material Settings
- Speed: 1700 mm/s
- Power: 24%
- Frequency: 30 kHz
- Line interval: 0.04 mm
- Passes: 1
At these settings, the result appeared good during initial materials-style testing.
Controls and Comparison Tests
The following were tested to isolate the problem:
- File / Artwork Validation
- Verified LightBurn Preview renders correctly.
- Created a fresh new file after rebooting both the laser and the computer.
- Confirmed the text object was the only geometry present.
- Confirmed there were no hidden objects or duplicate shapes.
Result:
The issue does not appear to be caused by bad artwork, hidden objects, or preview mismatch.
- Mode Comparison
- Plain Fill: artifact present
- Line: prints correctly, no comparable artifact
- Offset Fill: prints correctly, no comparable artifact
Result:
The problem appears specific to plain Fill mode.
- Bidirectional Fill Test
- Bidirectional Fill was disabled and the job was rerun.
Result:
No change. Artifact remained.
- Timing Override Tests
Override Default Timings was tested with multiple values.
Auto-populated override values:
- Jump Speed: 4000 mm/s
- Min Jump Delay: 10 µs
- Max Jump Delay: 85 µs
- Jump Distance Limit: 10.0 mm
- Laser On TC: 100 µs
- Laser Off TC: 100 µs
- End TC: 100 µs
- Polygon TC: 100 µs
Additional reduced timing tests were also attempted by lowering:
- Laser Off TC
- End TC
- Polygon TC
Result:
No meaningful change. All timing override tests produced the same Fill failure.
- Dot Width Adjust
Dot-width adjust was reviewed during troubleshooting.
Result:
It was already off by default and was not the source of the issue.
- Internal Materials Test Comparison
The internal Laser Tools → Materials Test was run and did not show the same obvious overburn artifact.
Result:
This suggests the issue may be geometry-dependent or related to how custom Fill jobs are grouped/scanned, rather than Fill being universally broken in all contexts.
Current Assessment
Based on the above tests, the issue appears to be specific to plain Fill behavior in this LightBurn + Monport 10W UV hardware combination.
Reasons:
- Preview is correct
- Artwork is clean
- Line mode works
- Offset Fill works
- Plain Fill fails consistently
- Disabling bidirectional fill does not resolve it
- Timing overrides do not resolve it
- Overburn becomes more obvious when shapes share horizontal scan territory
- Materials Test does not show the same visible behavior
Temporary Workaround
Offset Fill is currently the workaround for text engraving.
