Black Marking

A common requirement for laser marking is to achieve a high optical contrast without the surface being mechanically damaged by the laser. These criteria are particularly important for laser marking in the food industry and in medical technology.

However, this is also a frequent requirement for rotationally symmetrical bodies, as marking or engraving would change the mass moment of inertia and permanent concentricity could not be guaranteed. The solution to this is a special marking process known as black marking.

In black marking, the laser heats the surface of the material and the underlying volume.
The laser causes the metal lattice to vibrate, allowing the carbon trapped in the structure to diffuse to the surface. This deposition is then perceived as black marking.

Black marking offers a whole range of advantages for the permanent marking of a wide variety of materials, the most important of which are briefly presented here. If you have any further questions about the possibilities of black marking your products, please do not hesitate to contact us. Our experts will be happy to advise you individually.

The strong contrast between the black marking and the surrounding metal surface ensures very good legibility from almost all viewing angles, even in unfavorable ambient conditions. The markings are also matt, low-reflection and have a high resolution, making them ideal for machine-readable codes (read-back capability).

Black marking is permanent, but does not significantly change the chemical composition of the treated surface, so that the corrosion resistance of stainless steel and other alloys is maintained. This makes black marking particularly suitable for the permanent application of Unique Device Identification codes (UDI) and similar markings on medical devices, medical instruments and other products.

Thanks to the extremely short pulse duration of the ultrashort pulse lasers, black marking does not result in any significant heat input into the treated workpiece (cold laser marking). This prevents weakening or damage to the material, for example through stress cracks. There is also no roughening of the surface.

Classic fields of application for black marking are metals or alloys such as steel, copper, brass or aluminum.

Both black marking and annealing marking use laser energy to create a permanent marking. With annealing marking, however, heat is applied to the substrate to create a color change. This inevitably leads to a change in the material properties, which is not always desirable.

Our laser systems are controlled using our in-house Magic Mark laser software. This is deliberately designed to be user-friendly and offers you complete freedom when creating your markings.