The technique of using a clean-up pass is applicable for nd:YAG and fibermark lasers. When laser marking metal products with an nd:YAG or fibermark laser, the laser beam often causes the carbon to rise to the surface or excess residue to be leftover. This can be easily seen in stainless steel. Common sense would lead you to believe that an increase in power is the best solution. But in situations like this, using a lower power for the clean-up pass is typically the most effective. This is extremely useful if you are after a frosted look.
You will have to spend a bit of time to experiment with which settings work the best for your laser. If you keep your laser settings unchanged from your original pass and simply decrease your power, you should end up with a proper laser mark. For our 75-watt nd:YAG laser, we reduce our original power setting by approximately 40 to 50 percent to obtain a nice clean frosted effect.
-Richard Korbyl, Columbia Awards