The below guide discusses plastic laser marking along with its various applications.
With a fiber laser you can mark a wide range of plastics. Due to the different chemical compositions of the plastics, the result is very different. While the marking result with a conventional fiber laser is very good with some plastics, other plastics are less homogeneous or rich in contrast when marked. These plastics - especially dark plastics (e.g. PA 66 GF, PA 6 GF, PP GF, etc.) - can often be marked much lighter or more homogeneously with a MOPA laser. The advantage of the MOPA technology is the selectable pulse durations of the laser. This results in more options when choosing laser parameters. This can lead to a better marking quality, better contrasts, etc. for the plastics mentioned above.
The material is heated during laser marking. By heating the material, the color of many plastics changes (e.g. by changing color or carbonizing), resulting in a contrast and thus the marking. In conventional fiber lasers, the pulse duration is relatively long (100 ns), whereby the material burns or boils up or foams in some plastics. For these plastics (e.g. many dark plastics that turn light), the MOPA laser provides the ideal solution.
Thanks to the short pulses, which can be variably adjusted (between 4 and 200 ns) with the MOPA laser, and the low pulse energy, the surrounding material is less heated. Thereby, the material burns less and foams less. Especially on dark plastics, the shorter pulses can often produce “nicer”, lighter laser markings. This results in a better contrast and thus better (machine)-readability.
These dark plastics are characterized by a high reactivity to the laser beam. Thus, short pulses with relatively little heating of the material are necessary and sufficient here. In addition, there are also plastics that require more energy to sufficiently foam or boil up the material. Here, both a conventional fiber laser with longer pulse durations and high pulse energies and the MOPA technology are suitable. With the MOPA laser, even longer pulses are possible, whereby the controlled foaming can be optimized.
All laser systems of the SpeedMarker series are now also available with MOPA Laser. Depending on the requirements and the application, you can choose between laser workstations in different sizes, a table marking station or an open class 4 system.
Higher-contrast and more homogeneous marking of dark plastics is, however, only one application example where the MOPA laser can display its strengths. Even when marking metals such as e.g. steel (reproducible colors on stainless steel) or aluminum (black marking on aluminum), the all-rounder outperforms conventional fiber lasers.