The main advantages on metal are permanence, surface integrity, fine resolution, and speed. The mark is grown or cut into the metal, so it does not peel or fade like ink, and annealing can identify a part without removing material. A focused beam resolves small codes for traceability, and galvo scanning marks fast with no consumables, both holding for metal specifically.

Not when it is controlled: annealed marking grows a thin surface oxide without removing material, leaving the base metal and its mechanical properties intact. Heat input is held to a small, controlled zone so thin or precise features are not distorted. Deeper engraving removes material by design, so depth is specified where surface integrity is critical.

Aluminum yes, reflective metals with more care: bright aluminum marks well with the right parameters, often as a dark contrast. Copper, gold, and silver reflect strongly at 1 µm, so they need more power, a MOPA source, or in some cases a UV laser for reliable results. The more reflective the metal, the harder the fiber wavelength has to work.

A fiber laser mark is permanent in the way ink is not, because it changes the metal itself. Engraved and etched marks remove or restructure material and do not wear off in normal service. Annealed color marks are durable but temperature-limited, fading under sustained heat, so the mark type is chosen to match the part's environment.

Match the wavelength to what the material absorbs: fiber near 1 µm is the choice for metals, giving permanent, high-contrast marks. CO2 at 10.6 µm suits organics such as wood, acrylic, paper, and glass, where it cannot mark bare metal. UV at 355 nm marks heat-sensitive plastics and reflective metals with minimal heat, so the material decides.