The annealing method of laser marking metal
Annealing involves applying heat to metal to make markings. The heat creates a change in the structure of the metal that results in recoloration. During annealing, a defocused laser beam allows you to introduce only low heat into the material. The surface is not damaged, and remains smooth and clean. The temperature used during the process affects the resulting color and contrast of the markings. The MOPA fiber laser allows you to select pulse durations, which subjects the metal to less heat, providing wide range of laser parameters and more marking options. Adjustable pulse rates can generate deep black or different colors.
More information on MOPA fiber laser sources.