Laser Marking for medical devices

Since the MDR requires unique device identification, marking is no longer a minor matter. The UDI must remain permanently legible — on reusable instruments across hundreds of reprocessing cycles with alkaline detergents, ultrasound and steam. Laser marking is the usual method because it needs no additives and the mark is formed in the material itself.

Technically there are three routes, and they differ on corrosion. Annealing creates a coloured contrast through controlled oxidation without removing material — the passive layer is altered, not destroyed. Engraving removes material and leaves a rough recess in which residues can lodge. Black marking with very short pulses produces deep black with minimal heat input and has become the norm for instruments.

For buyers, what happens after marking is decisive. A mark on stainless steel should be passivated, otherwise corrosion starts there — at precisely the spot meant to stay legible. And legibility should be verified, not assumed: the quality of a data matrix code is assessed to ISO/IEC 29158, and after reprocessing, not before.