Many plastics can be marked with the conventional fiber laser. Most of the time, the marking result is very good, but for some plastics, the same level of homogeneity cannot always be achieved. These types of plastics can then be marked with a MOPA laser, which results in much more contrast and homogeneity. The adjustable pulse durations, which allow either short or long pulses, also help.
With dark plastics (such as PA 66 GF, PA 6 GF, PP GF, etc.), the surrounding material is less heated thanks to the short pulses and the associated low pulse energy. The plastics foam less and the marking is more homogeneous. Other plastics require more energy to heat up the material sufficiently. In this case, the long pulses help to optimize the foaming of the material. In both cases, marking with the MOPA laser leads to a more clear contrast and therefore to better (machine) readability.