Trotec laser engraving and laser marking machines can mark and engrave several different types of metal. This is primarily done using a laser machine with a fiber laser source. Methods include: annealing marking, engraving and removing. Below is an explanation of the different methods.
Find more information about different laser types here.
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.
The engraving method for marking metal
Unlike annealing, engraving involves changing the surface of the metal. During engraving, more energy is introduced than with annealing to vaporize the material or to make depressions in the surface. The engraving method creates a high-quality, abrasion-resistant mark that stands up over time even in the harshest environments.
The removing method of marking metal
The removing method of marking metal, like the name implies, involves removing the top layer of the material by laser processing. This is generally used for marking coated metals such as anodized aluminum. This process can performed at high speeds, and can generate high-contrast markings (as long as you are using a metal with a suitable top layer).
Bare metals can be marked with a CO2 laser only with the help of laser marking solutions such as paste, spray or tape. The metal marking solutions are applied to the workpiece and are burnt into the material during the laser processing. After the laser process, the remainder of the marking paste must be washed off. In this way, you can also achieve high contrasts on metals with weak absorption with a CO2 laser.