KERFBY KINETIC CARVING
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LightburnModule 2.3~3 min read

Fill Modes & Hatch Patterns

Hatch is how a galvo fills an area. Get the hatch wrong and a clean design comes out streaky, blotchy, or with visible scan lines.

Key parameters

  • Line interval: distance between hatch lines. Smaller = more overlap = denser, slower mark. Typical: 0.01 to 0.05 mm.
  • Scan angle: direction of the lines. 0° = horizontal. Rotate by 5-15° between passes to mask scan-line artifacts.
  • Cross hatch: fires twice at perpendicular angles. Use for solid blacks and deep engraving.
  • Bi-directional: on by default; turn off for ultra-fine work where galvo stop-start jitter shows.
SINGLE HATCH · 0°every pass runs the same wayOne direction. Banding and scanlines stay visible in the mark.Fine for photos and dithers.CROSSHATCH · 0° + 90°second pass fills the gapsTwo passes at right angles. Use itfor solid blacks and for deepengraving.ROTATE EVERY PASS20°, then 27°, then 34°Even start angle, odd step. No passre-cuts the last one's grooves, somulti-pass work stays flat.
Scan angle is the direction the fill lines run. The lines are drawn far apart here so you can see them; on a real mark they sit hundredths of a millimeter apart.

Pattern recipes

GoalPatternIntervalAngles
Dense black on stainlessCross hatch0.01 mm0° + 90°
Color anneal fieldSingle hatch0.02-0.04 mm0° (rotate 7° per pass)
Deep engraveCross hatch + perimeter0.015 mmalternate 0/45/90/135 per pass
Photo / ditherSingle, no rotation0.01 mm0° fixed
Tip
If you see banding on a black mark, the fix is almost always tighter line interval before increasing power.
INTERVAL TOO WIDEinterval larger than the spotUnburned stripes show betweenpasses. Fast, but streaky.INTERVAL MATCHEDinterval about equal to the spotEach pass just meets the last:an even, solid fill.INTERVAL TOO TIGHTinterval smaller than the spotEvery spot gets burned twice ormore: darker and deeper, but slow.
Line interval is the distance between passes. It is DPI upside down: 254 DPI is a 0.1 mm interval, 508 DPI is 0.05 mm. The red circle is the size of the spot.

Line interval by material (the fiber chart)

Interval is material-driven, not wattage-driven, which makes this chart one of the most transferable references in fiber work. It comes from long-term production practice on a 60W JPT MOPA-class source; treat each value as the starting point and adjust from your test grid.

Interval (mm)Material
0.02Titanium, carbon steel, tungsten, 3D / bitmap depth engraving
0.03Brass, copper, aluminum, gun slides. Covers roughly 90% of metals; the deep-engraving default
0.04Slate, river rock, most stone
0.045Glock polymer stippling only (proprietary polymer wants exactly this)
0.05Shallow metal engraving on thin stock ≤0.5mm deep (0.03 warps thin material)
0.06-0.07Synthetic leather (real leather looks bad on fiber, skip it)
0.08Hard plastics and polymers
0.1Soft plastics, rubber stamps, 3D prints, denim

The even/odd hatch discipline (multi-pass work)

For any job that runs repeated passes (deep engraving, relief, cutting rings), there's a simple rule that stops passes from re-carving the same grooves: scan angle EVEN, angle increment ODD. The classic pairing is scan angle 20° with a 7° increment. Because an even base plus repeated odd increments never lands back on the starting angle within a practical pass count, every pass hits fresh geometry and the floor stays flat instead of corrugated.

  • Scan angle: pick an even number (20° is the standard).
  • Angle increment: pick an odd number (7° is the standard). Keep auto-advance/rotate enabled so the increment actually applies per pass.
  • Keep 45° off the list for multi-pass work. It's the angle most prone to stacking visible artifacts pass over pass.
  • Single-pass photo/dither work is the exception, a fixed angle with no rotation is correct there (see the pattern table above).

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