Laser annealing is one of the best methods of adding high-contrast markings on ferrous and nonferrous metals without disrupting the material’s surface.
Laser annealing allows manufacturers to create markings on metal, plastic and other materials without disrupting the surface. It is most effective on steel, stainless steel and titanium. Unlike laser engraving, annealing does not remove material from the product — something that’s especially important in sterile environments where any crevice poses a threat of contamination.
The laser annealing process recolors the metal by heating it almost to its melting point and rapidly recooling it, causing internal oxidation to darken the affected area. As the laser pulses increase the temperature, the coloration becomes darker and darker until it leaves a black mark that stands out. A good laser annealing system may help you achieve other colors like brown, yellow and blue.
During the laser annealing process, manufacturers must control the energy density that’s going into a material in order to produce the appropriate darkness. Each material will mark differently than the last. The goal is to get your material’s temperature close to the melting point, causing the material to oxidize.
With the use of a MOPA (Master Oscillator Power Amplifier), laser annealing can achieve a greater variety of darkness. Varying the laser power can yield different results, which is done by adapting the pulse width of the laser.
Once the process is complete, the material will begin to cool, showing a resulting mark. Laser annealing is particularly appealing when it comes to ensuring wearability and survivability for the end user. It’s also a terrific process to support part traceability because of its ability to produce lasting results.
While all laser annealing processes generally work the same, there are a few laser types you can play with to get the right appearance:
Fiber lasers are the most common type of laser used for annealing. They are highly effective at making permanent markings on metals, rubber and plastics.
YAG lasers are lightweight and compact and work best on similarly delicate products. When you need small, precise markings or are working with a thin material, this laser is likely your best choice.
CO2 lasers work best as a heating mechanism or surface treatment rather than annealing. Still, in certain situations, they can be used to mark materials.
Regardless of the type of laser you use, having a quality laser annealing system offers benefits like:
Laser annealing can be useful in nearly any industry that uses metal tools, but it is especially common in:
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Whatever you have in production will look and perform even better when you use a laser annealing system to add those finishing details. Let Laser Marking Technologies show you a sample of what our tools can do when you contact us today.
