By laser marking a high contrast can be reached exclusively by ablation of a coating or cover material not as assumed by interaction with the material. For this a homogenous layer thickness, a high contrast between carrier and coating material as well as an high laser radiation absorbency of the coating are required.
Typical applications belonging to this process are for example the day-night-design by removing partially an opaque cover material from a transparent basic material, the production of name plates and apparatus front panels by ablation the anodic coating or layer of paint on stainless steel or aluminum or even the the processing of special multilayered, adhesive laser etiquettes.
By this process volume of the material is removed up to a depth of several tenth. Markings of this character mostly function as unforgeable, permanent and corrosion-proofed identification of components.
Metals which change their color under the influence of heat and oxygen can be marked by this process without any material removal and burrs on the surface. The markings are high in contrast and readable at temperatures up to 200 °C because of oxidation processes resulting in structural changes on the surface and finally in color changes.
The laser marking of polymers depends a lot on the materials properties and additives. By varying the energie input of the laser beam in the material different color changes can be processed. On the one hand a darker color by carbonation (thermochemical reaction) and on the other hand a lighter color by foaming (generate tiniest bubbles that were embedded permanent after cooling) are possible.
You can find more information in our datasheet.