Laser marking barcodes.
In this example, laser marking barcodes are used as part of the overall vehicle information plate, with the barcode containing the vehicles serial number information.
Anodised aluminium is a widely used material combination in today’s industrial markets. The ability to create a wide range of colours makes it ideal for many applications.
The laser process is used to remove the anodised surface, creating a very high contrast level. This contrast level is important in the reading of barcodes.
What is Anodising?
The process changes the microscopic texture of the aluminium by modifying the crystal structure near the surface.
The laser marking is used to vaporise the surface of the part removing the anodising from that area to expose the aluminium below. We have used an Nd:YAG Q switched laser in a low order mode to get the best results. The resulting image is very sharp and clean. Fibre laser could be used for this application as well.
Aluminium corrosion
The general consensus is, that an oxide layer very quickly forms to the surface providing protection to the material, preventing corrosion.
Can CO2 be used for laser marking barcodes?
CO2 can also be used for this type of laser marking application on anodised materials. With CO2 processing the dye is removed without any surface disruption taking place. While this can provide certain advantages (corrosion), the quality of the mark is difficult to maintain. CO2 will heat the plate, while attempting to remove the dye through a chemical reaction, and in doing so heat creep can occur. This shows up as blurred edges to the mark, and requires a very concise set up of the laser parameters.
