Some plastic materials such as this, are almost translucent to the wavelength of Nd:YAG and therefore difficult for laser marking. When the process starts, the laser marking can end up being sub surface causing implosions.
If the laser marking applications work is carried out correctly, the results can be very good. Here, an ID matrix code is marked, capturing the moulding data from a test station. The code is rectangular due to the amount of data required and the image area available. The laser focal position is set slightly out of focus. This creates a softer energy pulse form. This set up helps prevent the energy pulse passing into the material.
There are a number of differing changes to the plastic 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.
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.