Anodised aluminium engraving: settings that work first time

Aluminium is the metal the phone keeps ringing about. Anodised tags for hospitality, raw plate for engineering tooling, cast components for automotive, extruded profile for signage — every one of them takes a different set of parameters, and the wrong ones waste stock in minutes. This guide is a distilled, honest starting point across the four aluminium types we run every week, cross-checked against xTool's own published material guidance and dialled in on our own F2 Ultra Dual.

Anodised aluminium — the friendliest of the four

Anodised aluminium is one of the easiest substrates in the studio. Get it right and the mark is a clean, permanent contrast — either a bright white where the dye layer has been ablated to expose the aluminium beneath, or a sharp black where a short MOPA pulse passes through the transparent oxide and acts on the metal itself. Get it wrong and you smear the oxide into a muddy grey.

White marks — direction of travel

• Power: low — only as much as needed to lift the dye.
• Speed: fast — high speeds keep heat input down and stop the oxide melting.
• Frequency: mid-range on the MOPA fibre.
• Passes: one. If you need a second pass to see the mark, your power is too low or your speed is too high.

Black marks — MOPA only, direction of travel

• Pulse width: short — this is what lets the energy reach the aluminium under the oxide.
• Frequency: high.
• Power: low to moderate — you want a clean reaction, not melting.
• Defocus: kept tight on the surface for a sharp edge.

Raw and mill-finish aluminium — the annealing game

Bare aluminium has nothing to ablate, so a fibre laser can't produce the crisp black annealing mark you get on stainless. What it can do is a bright etched frost — the surface is micro-textured and reads as a light grey against the reflective backdrop. It's the standard finish for tooling numbers, jig identifiers and industrial nameplates.

• Power: high — 70–100% on the 60W MOPA is normal.
• Speed: slower than anodised — the beam needs dwell time to disrupt the surface.
• Frequency: low to mid (20–60 kHz) — longer pulses shift more material.
• Passes: 1–3 depending on depth wanted. Anything genuinely 'deep' needs multi-pass with air assist.

Cast aluminium — surface first, then settings

Cast aluminium (automotive housings, machine components, some cookware) is inconsistent by nature — you're marking through a mixed alloy with a slightly porous surface. Two rules that save time: (1) always clean and lightly degrease the part before you mark; residual mould release makes marks look inconsistent. (2) Run your test grid on the actual casting, not on a machined coupon, because the surface finish drives the result more than the alloy chemistry.

• Power: mid to high (50–90%).
• Speed: moderate — too fast and porous surfaces read patchy.
• Frequency: mid (30–80 kHz) works across most alloys.
• Focus: recheck between parts if surfaces vary in height.

Extruded aluminium profile — signage and mount rails

Extruded profile is usually the softest 6xxx-series alloy and takes marks predictably. The catch is length: profile jobs mean rotary or repositioning workflows, so the parameter question is usually second to the fixturing question. Settings-wise, treat it like anodised (if it is) or like raw aluminium (if it isn't) — extrusion doesn't change the physics, only the geometry.

Tooling and automotive parts — the accountability step

Tooling numbers, VIN plates, serial marks on structural components — these have compliance implications. Depth, contrast and legibility need to survive workshop cleaning, road salt, or ISO/UID readability requirements. In practice that means: known alloy, controlled surface, verified settings, and a documented parameter sheet you can hand to QA. Don't wing it on a job you've promised to certify.

How to dial it in for your batch

Anodising thickness, dye colour, alloy grade and surface finish all vary between suppliers — and often between production runs from the same supplier. The reliable workflow is: run a power/speed grid on a coupon from the actual stock, run a frequency (or pulse-width, on MOPA) sweep on the best square, then re-run the grid at that frequency. Aim for the lowest power that produces a fully opaque, even mark with a clean edge under a 10× loupe. Twenty minutes on a coupon saves hours on a production run.

Sources and further reading

• xTool official materials guidance — start here for the manufacturer's tested starting points on the F2 Ultra family.
• Laser Engineering 911 (YouTube) — long-form technical breakdowns on fibre / MOPA parameter theory that align with what we see in production.
• Your own supplier's spec sheet — always.