Each plastic has specific light absorption spectrum. The laser irradiation can generate direct chemical modifications, melting or evaporation of the material. Plastics are rarely seen in their pure state because several additives are used such as colorants, ultraviolet retardants. These additives impact the result of laser marking. For signage laser engraving , etc., special laser-marked plastics were developed. Outer of this material vaporize easily to expose different coloured material below. Other plastics may be successfully engraved, but we recommend the experimentation on a sample before sending PO. Expanded plastics like foam are generally candidates for routing rather than laser engraving. Many light switches from companies can be laser engraved. Again, experimentation may be necessary to develop the correct laser settings to result in engraving the surface rather than melting it. Often the laser engraving is followed by backfilling with paint on the engraved surface to produce more contrast between the engraved surface and the surrounding surface.