A good example of product branding by laser marking anodised aluminium is customer Dynamic Audio. It is used in high end audio accessories in the form of cable tidies. The aluminium is highly polished, prior to anodising, in order to achieve the high gloss finish on the part.
The laser process, delivers small pulses of energy to the component surface. These pulses have enough energy to vaporise the surface of the aluminium where the anodised coating occurs. This exposes the base material, aluminium, creating a high contrast result.
The product branding of the anodised aluminium is being used for aesthetic reasons, therefore, there are no technical issues with exposing the base material.
This electrolytic passivation is widely used across the industry on aluminium for a variety of reasons. The process can also provide a huge range of colour variations through the use of colour dying. The process changes the microscopic texture of the aluminium, by modifying the crystal structure near the surface.
Exposing the base aluminium like this provides a very high degree of contrast.
The general consensus is, as the laser removes the anodised layer, an oxide layer forms very quickly on the surface. This provides protection, to the material beyond the oxide layer thickness preventing corrosion.
Laser marking using CO2
CO2 can also be used for this type of application. CO2 wavelength could be used, however, in this instance, the dye will be removed, without any disruption to the material surface. While this can provide certain advantages, 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.
The combined precision of the beam placement, along with our tooling design means the part and mark are precisely aligned every time we set up a new batch of parts. Tooling design uses a cross slot and dowel locating system, while jigging is specifically designed to accommodate both simple and complex shapes as required. The operating software holds positional data, so that the laser and tooling are aligned.
If you would like further information on this application, or any other application, please request a call back or, talk to one of our laser marking specialists by going to our contact page – link below.