Color changing, foaming or engraving
The laser marking is carried out by intensive interaction of the laser light with the plastic. The high input of energy leads to carbonization of the polymer, to foam or to local removal of the plastic (engraving). The color change depends on the plastic material, its color and the laser intensity.
A further possibility is a controlled color change by special pigment additives.
A day & night marking of plastic components can be achieved by selective removal of paint layers by laser ablation until the translucent plastic material become visible.
Metals can be marked by annealing (color change by oxide formation) or by local removal (engraving).