In this page, you will learn how to produce black markings on coated metals, such as anodized aluminum, using a MOPA laser machine.
Anodized aluminum is well suited for laser processing and can be efficiently laser engraved by removing the top anodized layer to reveal white markings. Marking colored anodized coatings will ultimately produce the best results and black markings create higher-quality marks, whereas natural anodized aluminum creates a barely visible mark. With a MOPA laser machine, various gray tones all the way up to deep rich black markings can be achieved on natural anodized aluminum. This is a common application used to mark high-quality smartphones, as well as many more.
Shortened pulse durations can be set with a MOPA laser machine, which is the key to creating black marks on anodized aluminum. With this process, the short pulse durations repaints the material but does not remove the anodized layer or damage the surface. This technique is comparable to the production of tempering colors on stainless steel, but different in its own way. The filling line distance can be set to adjust in a wide range of varying shades from grays up to deep and rich black: The smaller the distance, the deeper the marked color becomes.
Using a 20 watt MOPA marking laser, we recommend the use of the F-254 lens as it fits the spot diameter for this application perfectly. The following parameters should also be set:
|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
It should be noted that coated or anodized layers can vary quite greatly with each material. The engraving page should always be used for processing black markings and if you need further assistance, contact us. One of our top qualified and highly motivated laser experts will gladly assist you with any additional questions or problems that you have.