Here we see a laser marked black anodised medical device. Forming part of below the knee prosthetic limb, this anodised aluminium part has been laser marked with the information placed around its circumference.
On this, as with many other similar parts, the marking details cover a range of requirements such as branding (as shown here), or technical information such as torque values on fixing positions or screw sizing.
In this example, we have used an Nd:YAG Q switched laser. The laser is used to vaporise the top surface to remove the area affected by the anodising process, thus exposing the host material. Where a darker dye colouring is used, the contrast levels remain high between the two contrasting surface areas.
The application in rotation
Here, we have used the flash lamped laser in conjunction with a rotary indexer. The job programme controls the rotation of the indexer for each of the marking groups in the sequence. As each position is reached, the indexer signals the laser to commence marking, removing the anodised surface area to expose the aluminium base materials. This provides the highest level of contrast for the marking.
Laser marking black anodised medical device using CO2 laser technology
CO2 lasers can also be used to process anodised parts. Generally, the wavelength of the laser allows for the removal of the anodised dye, producing a white mark with no material removal. However, it is fair to say, the quality of image would not be as good as can be achieved by the Nd:YAG or fibre laser. The main reason for this is, when removing the dye, it is difficult to control heat creep around the mark area. Heat creep results in what appears to be a blurred edge to the mark.
More examples can be found in our application photo library. For further information on laser marking, black anodised medical device or any other laser marking application, advise or costing details, please contact Thinklaser on 01737 826902.