Although bare aluminum is reflective at CO2 wavelengths, coated aluminum provides an excellent mark surface and is a large part of the market for CO2 laser marking. In many cases, the process of treating aluminum parts with a paint or anodize coating to prevent corrosion is already factored into the manufacturing operation so no additional costs are incurred.

This example was done to test the feasibility of replacing an inkjet marker with a laser marking operation. To do this, we setup an FH Series marking head with a 125 mm lens to obtain a 180-micron (0.007”) spot over a maximum mark field of 85 mm × 105 mm (3.4” × 4.2”). We then created a 25-character, two-line text string in WinMark Pro using the Simple stroke font and set a Text Height of 4 mm (0.155”). To mark the part number, we choose a Velocity of 381 mm/sec (15”/s) and a Power (duty cycle percentage) corresponding to 25 watts.

The accompanying photo shows the difference between a permanent CO2 laser mark and the existing inkjet mark (partially visible on the left). The cycle time required to mark this particular powder-coated part with 25 watts of power was 0.44 seconds.

Using 25 watts of power, we were able to mark a 25-character text string in a cycle time of 0.44 seconds per part.