Introduction
Lasers have long been recognized as an important marking tool for industrial applications, and it is hard to imagine what would happen without them in production. Whether it’s a pattern on a cell phone case or a scale on a watch, whether it’s letters on a keyboard or a design on a stainless-steel cup, it’s all marked by a laser marking machine. What is laser marking? Laser marking technology refers to the use of the thermal effect of laser on the material surface so that the substrate undergoes a series of physical and chemical changes, leaving a permanent marking technology.
Laser marking smaple
Principles and Applications of Laser Marking
The laser is focused on its specific wavelength and high-power density to mark the material causing a change in the material surface. The interaction between the material and the laser depends on the material to be treated, the wavelength of the laser and the choice of technical parameters (laser power, marking speed, Q-frequency, etc.) and the material absorbs a fixed wavelength of the laser, which changes material surface. Lasers can be marked by material removal, engraving, tempering, discoloration and fading, and foaming.
Material Removal
Coating materials can be marked by laser removal of the surface layer, such as anodized aluminum, painted materials, good transmissivity materials and laser-marked films. 
Engraving
Lasers can engrave metals, ceramics and some plastics. During the processing, the high-power density of the laser beam can cause some material to evaporate. The material is not mixed by color in engraving. The interaction of the molten material with oxygen in the air usually produces oxides that create color and make the mark more obvious.
Tempering
Metals can be marked by tempering. These materials are usually heated below their melting point. This process produces substructural changes that result in a visible hardening color. This color is hard to disappear at about 200℃. If the temperature continues to rise, the structural changes disappear as the markings disappear.
Discoloration and Fading
This process is necessary for plastics. Selectively changing the beam energy or destroying individual molecular structures such as pigments. The material and the laser wavelength must be optimally matched.
Material color is changed by absorbing laser energy in the energy-limiting properties. Changes in the color of the material manifest themselves in mechanical spots or the form of fading. The material surface remains virtually intact.
Foaming
The foaming process is only applicable to specific plastics. The laser beam melts the plastic. During this process, small bubbles are created that close as the material cools. This is a “relief” marking. The incident light is scattered at the point of application, producing a brighter effect compared with engraving.
Features of The Laser Marking
Laser marking is less costly, more flexible, and can be controlled by a computer system compared with traditional methods such as mechanical engraving, chemical etching, screen printing, and ink printing. For application to industrial marking, the following requirements are followed, such as marking durability, high contrast with the substrate material, integration and high productivity.
Conclusion
Laser marking by the laser generator produce a high-energy continuous laser beam causing the material surface to be instantly melted or even vaporized, and the desired marking pattern is formed by controlling the trajectory of the laser.