Machine used M Series laser marking system
Laser source Nd:YAG Q Switched laser
Application Branding and traceability details
Competion year 2016
Customer Risbridger
Material Aluminium, Anodised blue

In this example we are laser marking blue anodised aluminium, removing the anodising to expose the base material beneath.

The device,used in the petrochemical industry, contains both branding details and identification information. The part number identifies the part for ordering. The batch number is used for traceability.

A combination of the contrast created by laser marking blue anodised aluminium and large characters makes the product readable at distance. A maintenance requirement for the product.

Anodising explained

This electrolytic passivation, in this case blue, is widely used across industry on aluminium for a variety of reasons. The process provides a 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.

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.

Corrosion

The general consensus is that as the laser removes the anodised layer an oxide layer, very quickly, forms to the surface providing protection to the material beyond the oxide layer thickness preventing corrosion.

Processing with CO2 lasers

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 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.

If you would like further information on this laser marking application or any other application please request a call back or talk to one of our laser marking specialists on 01737 826902