Anodised aluminum can be engraved very well and quickly with a laser. The anodised layer is removed and a white marking is generated. This is particularly well suited for coloured anodised coatings. In the case of natural anodized aluminium, however, this marking is not very clearly visible, and the black marking is also of significantly higher quality. With a MOPA laser, natural anodised aluminum can be very nicely laser-marked in various grey tones up to a rich black. This process is also used to mark high-quality smartphones, among other applications.
The secret to black marking anodised aluminium is that you can set extremely short pulse durations with the MOPA laser. The short pulse durations do not damage the surface of the material and the anodised layer is not removed, rather it is just repainted. While the process is entirely different from the production of tempering colours on stainless steel, the result nonetheless is comparable. You can set the filling line distance to adjust in various shades of grey as well as black. Note the smaller the distance, the darker the markings.
You need a 20 watt MOPA laser to black mark anodised aluminium. We recommend using the F-254 lens because it perfectly fits the spot diameter for this application. We recommend setting 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
We would like to point out that the anodised layers can be very different. For this reason, always use the engraving page for the black marking. Our laser experts would be happy to assist you should you have any further questionss.
To ensure that the parameters we specify work, we suggest you purchase anodised aluminum from our product range.