The aim here is to provide product branding for the manufacturer. The product branding is for his customer base. Additional information is also applied to these trays which includes CE marking, part number etc. In both cases the marking process is the same and the results again, the same.
Silicon is quiet difficult to process using Nd:YAG. It is in the group of materials that can be translucent to the wavelength. In this case both the pigment and the surface finish aid in the marking being possible. Both of these help to create a barrier for abortion to the surface of the material rather than internally. We have processed the mark twice, in both cases with a very light mark. Low pulse count and low energy values. The first pass creates a more defined abortion barrier to the surface while the second pass heightens the contrast level to the surface. Resulting in a grey form of mark.
The laser marking of these material types falls between the two main categories of laser used in industry today (YAG and CO2). In this case we have used Nd:YAG laser marking for the plastics to demonstrate the marking process.
There are a number of differing changes to the material surface during laser marking and it is very dependent on the material itself as to which one occurs.
- A thermochemical foaming, creating gas bubbles to the surface of the material, is the most common. The light scatters across the affected area producing the light marking that appears.
- Bleaching is another effect that is common. Here the pigment used to achieve the product colour is removed creating a visual difference.
- The third mechanism is vaporisation where the material is heated, very quickly, to the point where it vaporises and is removed leaving behind the created image.
These three laser marking effects can be enhanced by the adding of laser sensitive additives and can generate considerable advantages. The additive acts as an abortion barrier boosting the ability of the laser to process better. In some materials the laser marking ability would not be possible without this additive.
Materials that are naturally white and contain no additives tend not to mark very well. They tend to be semi or fully translucent to the wavelength of Nd:YAG. They can be marked using CO2 but no contrast is normally achieved. The general rule is fully test before deciding the most appropriate marking to be completed.
If you would like further information on this laser application, or any other application, please request a call back or talk to one of our laser marking specialists on 01737 826902.
