Material · coated metal

Laser engraving settings for anodized aluminum

On anodized aluminum the laser does not engrave the metal: it clears the dye out of a thin oxide skin and leaves a white mark. Bare aluminum has no dye to remove and bounces much of the light back.

Safety first

Before you start Usually fine

  • Anodized aluminum is in the “engrave” column for diode and CO2, and fiber marks it (diode vs CO2 vs fiber). The mark is the dye being removed: Trotec says very little of the anodised coating itself is removed.
  • Bare, polished aluminum is a different job. It reflects much of the light; sources disagree whether a blue diode marks it at all, CO2 does not, and fiber does. A shiny part can throw stray reflections — keep the shield closed and wear goggles rated for your wavelength.
  • Painted or powder-coated aluminum is not anodized. Glowforge asks you to check that a powder coat contains no PVC (what not to laser cut).
Moving cross-section

What the beam does

Switch the material or laser and watch the same beam give a different result.

Blue diode ≈ 450 nm
  • Dye sealed in the pores
  • Anodic oxide (drawn far thicker than real)
  • Aluminum

The beam clears the dye from the top of the oxide layer. The white oxide shows through; the metal underneath is untouched.

Cross-section, not to scale.

Laser types

Which laser can process it

These are this material’s rows from our diode vs CO2 vs fiber matrix. (full matrix)

Anodized aluminum

Blue diodeEngraves only
CO2Engraves only

Removes the dye and leaves a white mark; the anodized layer stays.

FiberMarks / engraves

Bare aluminum

Blue diodeSources disagree

One source says a blue diode does nothing to bare metal; two list aluminum as engravable.

CO2Not suited
FiberMarks / engraves
Maker values

Maker settings on one scale

Every value is a starting point published by the maker, and the maker is the source; none of them were tested by us. Machines differ in optical power, so power % and speed are converted to the energy the beam puts into each millimetre of line (J/mm). Tap a point or a table row to see the original row, the math and a link that fills in the converter.

J/mm = optical W × power % × passes ÷ speed (mm/s) · J/mm² = J/mm ÷ line interval (mm)

This is the same formula as the converter. Between lasers of the same type, similar J/mm gives a similar burn. Cutting energy rises steeply with thickness, so compare rows of similar thickness.

AtomStack labels most of these rows “Alumina” (aluminum oxide — the layer anodizing grows); the table does not define the word, so we read them as anodized aluminum. “Aluminum card” and “Aluminum Business Card” are the blank cards sold for engraving. The IR rows are 1,064 nm modules (P1, Kraft), plotted as triangles. TwoTrees’ rows say “Anodized aluminum” outright.

0.0010.010.1110125102050100Optical power (W, log scale)J/mm (log scale)0.0010.010.1110125102050100Optical power (W, log scale)J/mm (log scale)
▬ Half of Engrave rows: 0.0609–0.28 J/mmEngraveDiodeCO2IR 1,064 nmA40 Pro V2 is calculated at 48 W (the table does not say whether it is the 48 W or the 24 W setting).
31 rows
Machine (optical W)SoftwareMaker label · thicknessJobSpeed mm/minPowerIntervalPassesJ/mm
LightBurnAluminaEngrave30080%0.111.6Convert →
LaserGRBLAluminaEngrave300S8000.111.6Convert →
LightBurnAluminaEngrave3,00080%0.0810.32Convert →
LaserGRBLAluminaEngrave3,000S8000.083310.32Convert →
LightBurnAluminaEngrave10,00080%0.0810.115Convert →
LaserGRBLAluminaEngrave10,000S8000.083310.115Convert →
LightBurnAluminaEngrave10,00080%0.0810.115Convert →
LaserGRBLAluminaEngrave10,000S8000.083310.115Convert →
LightBurnAluminaEngrave10,00065%0.0810.187Convert →
LaserGRBLAluminaEngrave10,00065%0.083310.187Convert →
LightBurnAluminaEngrave10,00055%0.110.231Convert →
LaserGRBLAluminaEngrave10,000S5500.110.231Convert →
BitmapAluminaEngrave18,00035%0.110.0642Convert →
Vector LineAluminaEngrave3,50040%—10.377Convert →
BitmapCoated aluminaEngrave10,00080%0.0110.0058Convert →
Vector LineCoated aluminaEngrave50060%—10.0864Convert →
BitmapBlack aluminaEngrave10,00070%0.0110.005Convert →
Vector LineBlack aluminaEngrave50060%—10.0864Convert →
BitmapAluminum cardEngrave10080%0.0512.4Convert →
Vector LineAluminum cardEngrave10080%—12.4Convert →
BitmapBlack aluminaEngrave1,00080%0.0510.24Convert →
Vector LineBlack aluminaEngrave1,00080%—10.24Convert →
BitmapAluminaEngrave6,00080%0.0810.16Convert →
Vector LineAluminaEngrave50020%—10.48Convert →
BitmapNatural color aluminaEngrave1,00080%0.0110.0576Convert →
BitmapCoated aluminaEngrave6,00080%0.0210.0096Convert →
Vector LineCoated aluminaEngrave1,00030% (constant power)—10.0216Convert →
BitmapAluminum Business CardEngrave5,00060%0.0210.0086Convert →
Vector LineAluminum Business CardEngrave500100%—10.144Convert →
-Anodized aluminumEngrave4,00060%—10.0495Convert →
-Anodized aluminumEngrave6,00020%—10.02Convert →

What the laser actually removes

Anodizing grows a thin, porous aluminum-oxide skin on the part; colour comes from dye sealed into those pores. A laser clears the dye and exposes the plain white coating underneath — Trotec describes exactly this, and notes that very little of the coating is removed, so the part keeps its protection. That is why the mark is white or pale grey whatever the colour, and why black and dark blue give the best contrast while natural (undyed) anodizing gives very little.

Because the coating is hard and does not melt or bleed like wood, Trotec recommends a fine resolution of 600–1,000 ppi — a line interval of about 0.042–0.025 mm (line interval & DPI calculator). Most maker rows for diodes use 0.08–0.1 mm; the 1,064 nm rows use 0.01–0.02 mm.

Anodized vs bare aluminum

Bare aluminum is one of the most reflective metals in visible light: reflector-grade sheet is sold with at least 93 % reflectance at 450 nm (Chalco L95), right where a blue diode sits. Plain sheet is less shiny than that, but the point stands — most of the beam leaves instead of heating the surface. Our sources split on whether a blue diode marks bare aluminum, list CO2 as unable, and list fiber as the tool for it.

So if a “metal business card” will not mark, check whether it is anodized at all. For bare metal, the options are a fiber or 1,064 nm module, or a marking spray with a CO2 laser (see diode vs CO2 vs fiber).

Prep, focus and finish

General shop practice (no source):

  • Clean off fingerprints and oil before engraving; they show up as patches in a fine fill.
  • Focus carefully. Trotec notes that blurred edges mean the focus is off — on a thin card, measure from the card’s top face, not the bed.
  • Hold it flat. Thin cards curl; tape the corners or use a jig so the focus does not change across the card.
  • Stop when it is white. Once the dye is gone, more energy does not make the mark whiter. Go up only until the mark stops improving.

How to run an anodized test

  1. Use a scrap from the same batch: colour and coating vary between suppliers.
  2. Run LightBurn’s Material Test with power against speed at a fixed fine interval (LightBurn).
  3. Choose the box with the cleanest, most even white at the lowest energy.
  4. If nothing marks at all, it may not be anodized — or your wavelength is the problem (bare metal).

FAQ

Can a diode laser engrave anodized aluminum?
Yes. Anodized aluminum is listed as engravable with a blue diode, and AtomStack and TwoTrees both publish diode settings for it. The laser removes the dye and leaves a white mark; it does not cut into the metal.
What settings do makers give for anodized aluminum?
AtomStack’s diode rows mostly run 3,000–10,000 mm/min at 55–80 % with a 0.08–0.1 mm interval, about 0.1–0.3 J/mm per line, with a few slow rows (A10 Pro V2, P1) far higher. TwoTrees gives 4,000 mm/min at 60 % (5.5 W) and 6,000 mm/min at 20 % (10 W). Scale them to your machine and test.
Why will my diode not mark an aluminum business card?
Check that it is anodized. Bare, shiny aluminum reflects much of the blue light, and sources disagree whether a diode can mark it at all. Anodized cards have a coloured surface; bare ones look like plain metal.
Does laser engraving damage the anodized layer?
Very little, according to Trotec: the laser exposes the white coating and removes very little of the coating itself, so the protective layer stays. Mechanical engraving goes deeper and can cut through to bare metal.

Sources

Sources for the laser-type verdicts

Last checked 2026-11-01 · Maker values and calculations; we did not process this material ourselves.

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