The comparison between the machining results achieved with a ps laser and those achieved with an ns laser showcases some interesting aspects.
The machining of stainless steel with ns lasers, e.g. via the LEO 15W workstation, generates annealing colors. This type of laser marking has been a well-established process for over 20 years.
The drawback of the process consists in the angular dependency of the annealing colors: the surface is too glossy and the labeling is barely visible at certain observation angles. In addition, the machined area is susceptible to corrosion.
By contrast, the processing of stainless steel with the ps laser produces different characteristics. The surface is black again but without the drawbacks mentioned above. There is no angular dependency; the laser marking is black from all viewing angles. There is no susceptibility to corrosion.
These fascinating properties are particularly interesting for surgical tools but can also be used e.g. for sight screens. The picture above shows a surgical tool with the corresponding marking.