By using a MOPA laser, you can set very short pulse durations. This technique is the key to sucessful black marking of anodized aluminum. One of the benefits of this technique is that the short pulse durations eliminate damage to the surface of the material. The anodized layer is not removed, but just repainted. Although the process varies from the production of tempering colors on stainless steel, the end result makes for an excellent comparison. You can set the filling line distance to adjust in a wide range of various shades of gray up to black: The smaller the distance, the darker the marking gets.
You need a 20 watt MOPA laser to mark anodized aluminum black. We recommend using the F-254 lens because it perfectly fits the spot diameter for this application. You should set the following parameters:
|50%||1500 mm/s||200 kHz||8 ns|
|Focus||Filling lines distance||Passes|
|In focus||0.001 mm bidirectional for a rich black |
0.002 - 0.005 mm bidirectional for gray tones
Keep in mind that the anodized layers can be very different. Be sure to always use the engraving page for black marking. If you are ever in doubt and have further questions, our experts from the application laboratory will be happy to help. To ensure that the parameters we specify work, we recommend that you purchase anodized aluminum from our product range.