Annealing lettering
With annealing lettering, the color of metals is changed with a laser. This is done under the influence of heat and oxygen without the removal of material. With this purely thermal process, certain metals are heated locally to below their melting point. An oxide layer is created at the surface and determines the color impression by its properties. Finished surfaces can be lettered later by annealing.
1: Scanner 2: Objective 3: Laser beam 4: Work piece 5: Cooled, discolored area