Laser marking is defined as lettering or marking objects using an intensive laser beam that alters the material itself. The method and the energy use therefore depend on the material. Laser markings are water and effacement resistant and very durable. They can be produced quickly, automatically, and individually, which is why the method is popular for numbering of individual parts. It can be used also, in order to apply small machine-readable markings such as barcodes or data matrix codes directly on products. Depending on the material, different effects can be obtained with laser marking.
With organic materials like paper, cardboard, wood, or leather chemical transformation reactions are triggered by the local heating and result in color changes, comparable to the application of a burn mark. Even with organic plastics this effect can be produced, frequently special plastics are used, with which the heating produces a specific color change. Thus the spectrum of attainable color variants expands. Computer keyboards are an example for this method.
Another type of laser marking is the specific pain removal from coated objects so that the underlying color of the objects is revealed. With this method and using specially coated, adhesive foils, identification plates, vignettes, and other adhesive labels can be manufactured very economically and in small series. Another variant is engraving colored anodized or elox coating on aluminum. Here the anodized or elox coating is burned by the laser, and the shiny aluminum forms the actual text color.