Up until just a few years ago, color laser marking was impossible. Lasers were limited compared to alternative technologies, which was an enormous disadvantage.
Today, with the advancements in technology and software-level parameters, we have achieved significant results for color — even in the brightest, most defined tones.
Color laser marking is a process that works by regulating the laser’s refraction index, forming a transparent or semi-transparent oxide film. The colors vary based on the type of material being processed.
Basically, if the marking process usually engraves the surface of
the material, its physical structure, this
process only changes the oxide layer, creating a color contrast effect.
Below is a video on color marking a steel plate using a 30
Watt MOPA fiber laser
Today, color marking on steel is very popular, as this material responds the best to the process and can be used to create a wide range of colors. Once again, the parameters that influence the final result are laser frequency, power, speed, focal distance, and more.
This article explains how pulse power and time influence laser marking.
How does color marking work? Color marking requires a specific focal beam. Pulsed and continuous lasers are both suitable for this process, but we always recommend the MOPA fiber laser, which is the most suitable for its properties and performance.
The pulse length and other variables determine the quality of the heat that touches a product’s surface. During the color marking process, the focused energy is used to change the molecular structure of a material. With plastic, localized heat allows darker or lighter tones to be created on the material, and the material’s composition determines the color. When working on metal, color marking requires the precipitation of a carbon layer on the surface, which often translates into a color tone.
In this process, moving the laser out of focus at times can help prevent damaging the material, which is very important in medical marking. And while working with a Master Oscillator Power Amplifier (a MOPA laser), it is even possible to modify the waveform.
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