This example shows laser engraving anodised Aluminium scaling. The laser delivers small pulses of energy which heat the material surface until it vapourises. This removes the layer that contains the black anodising exposing the base material below. Providing the required contrast between the two finishes.
The application
To create linear guides by laser engraving anodised aluminium.
The guides are for the side of a machine providing a quick positional reference. In this example, the full scale is much larger than the process area available. It was necessary to create tooling that allowed us to move the material after each 200 mm section was marked, ensuring the scaling was accurate.
To achieve consistent white marks on aluminium, the correct laser power, repetition rate, marking speed and image fill ratio must all be selected. With most aluminium’s a slight deviation, either way, from your standard settings, should be enough to pull back any variation you see. In some cases, it may also be worthwhile considering a second pass, with much lower power settings to lightly skim the image, removing any burning caused by the initial process pass.
The quality of the finish on the aluminium, is greatly dependent on the material quality. With poor quality materials (high levels of alloys), the grain structures have a tendency to tear leaving rough surfaces and edges. The higher the quality of the base material, the higher the quality of the mark result, and the closer to white the mark will appear.
The combined precision of the beam placement, along with our tooling design, means that jobs such as this can be created to high levels of accuracy, without adding unnecessary cost.
What is Anodising?
Anodising is an electrolytic passivation, widely used across industry on aluminium for a variety of reasons. The process changes the microscopic texture of the aluminium, by modifying the crystal structure near the surface.
Aluminium corrosion
The general consensus is, 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.
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
