Metal Engraving, Marking & Identification

Marking (annealing) changes the surface color without removing material: controlled heat grows an oxide layer, usually black or dark gray, and the surface stays smooth. Etching melts a very thin top layer, leaving a fast, high-contrast mark you can feel with a fingernail. Engraving removes material to cut an actual recess — deeper, more wear-resistant, and slower, built up over multiple passes rather than one high-power hit. Choose by how much depth, contrast, and durability the part needs: anneal for clean color marks, etch for fast contrast, engrave for depth.

Yes — that’s annealing. The beam heats the surface to grow a controlled oxide layer, producing a black or colored mark that sits flush with the surface, with no recess and no material removed. Because the surface stays smooth, it’s the preferred method for medical, food, and corrosion-sensitive parts. The same oxide effect, with tuned fiber settings, is what produces controlled color marks on stainless.

On anodized aluminum a fiber laser bleaches the dye layer to a bright white mark with very little power and high speed — fast, high-contrast, and no consumables. It’s also one of the few metals a CO2 laser marks directly: the beam bleaches the colour out of the thin dyed anodic coating without removing it, giving a crisp white-frost-on-dark mark with the coating intact. Either way, run lower power and higher speed and test on scrap — too much energy cuts into the aluminum and dulls the contrast. Bare (non-anodized) aluminum is different: it needs a fiber laser or a marking spray.

A smaller field lens concentrates the beam into a smaller spot for the finest detail; a larger field lens covers bigger parts in one pass, but with a larger spot. On a galvo marker the lens sets the mark field the mirrors can scan (see the beam-path diagram above), so lens choice is a throughput decision as much as a detail one. Match lens and field size to your part dimensions and the smallest feature you need to resolve — the lens & field size guide walks through it.

An annealed or deep-engraved mark resists abrasion and corrosion far better than a surface etch. Annealing leaves the surface smooth and corrosion-safe, which is why it’s the go-to on stainless and titanium; deep engraving cuts a recess that survives heavy handling and refinishing. A shallow etch, by contrast, can often be sanded or polished back — the wrong choice when a mark must be tamper-resistant. For parts exposed to wear, cleaning, or weather, choose annealing or engraving and validate the mark against your read and durability requirements.

Match the laser to the metal first. A fiber laser’s 1064 nm beam is absorbed by bare stainless, aluminum, brass, copper, and titanium, so it anneals, etches, and engraves directly with no coating; a CO2 laser only marks bare metal with a marking spray such as CerMark or LaserBond; a UV laser makes low-heat, high-precision marks on sensitive parts. Then set focus accurately, choose the mark type — anneal for color, etch for fast contrast, engrave for depth — and balance power against speed: more energy means deeper and darker, and deep engraving builds up over multiple passes. Run a small test grid on scrap of the same alloy before committing to the part. More short answers live in our engraving FAQs.

You can get a mark on stainless with a diode laser, but the dependable method is a stainless marking spray or paste. On bare stainless a diode usually leaves only a faint, low-contrast surface mark and cannot anneal the steel the way a fiber laser does. For fast, consistent, dark, production-grade marks on stainless, a fiber laser is the right tool — the fiber FAQs cover more wattage and material questions.

For marking and etching most metals, a 20–50 watt fiber marker is the practical sweet spot and handles the vast majority of jobs. For deep engraving or faster throughput on harder alloys, step up toward 50–100 watts. Wattage is only part of the picture — beam quality, focus, and the metal itself matter just as much. As a rule of thumb, a hobby-class diode in the single-digit-to-low-double-digit watts is for marking coated or anodized surfaces, while genuine bare-metal engraving starts with a fiber laser.