Laser marking of plastic water saving device

Plastics fall into a group of materials that can create many different issues when laser marking. Method of moulding, colour inclusion, surface finish, additives, all play a part in determining if the material will mark to an acceptable level. Some materials will mark if a colour additive is used but will not process the material in its base form. In this case, an Nd:YAG pulsed laser marking system is used with a very low pulse rate and power setting. Two passes are used , the first creating the absorption barrier and the second to darken the image up. The results being reasonably good. The mark is permanent and will withstand the environmental conditions the part is expected to operate within.

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.

1. 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.
2. Bleaching is another effect that is common. Here the pigment used to achieve the product colour is removed creating a visual difference.
3. 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.

These were part of applications proving for the customer and never turned into a real job. Co2 was also tested on the materials. While it will mark the plastic there is no resulting contrast to the surface.

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.