Laser marking
and laser engraving plastics

When laser engraving and laser etching plastic, it is possible to achieve a permanent mark on a number of different types of material, although the various raw materials as well as colour pigments and other additives (e.g. fillers, additives, flame retardants) react very differently.
For laser marking plastics a fiber laser offers you a range of different methods, such as dyeing, carbonation or foaming. Prior to laser engraving, laser cutting or laser marking plastic you should always use a test piece as different materials react differently to processing.

Here are some applications:

• Housings made of plastic
• Electric plugs

• Electronic components
• Printed circuit boards (PCB)
• Automotive parts
• Keyboards
• Tools and handles of tools
• Buttons and switches with day & night design
• Identification tags for animals
• Packaging
• Films
• Sensors

Many plastics can be marked with the conventional fiber laser. Most of the time, the marking result is very good, but for some plastics, the same level of homogeneity cannot always be achieved. These types of plastics can then be marked with a MOPA laser, which results in much more contrast and homogeneity. The adjustable pulse durations, which allow either short or long pulses, also help.

With dark plastics (such as PA 66 GF, PA 6 GF, PP GF, etc.), the surrounding material is less heated thanks to the short pulses and the associated low pulse energy. The plastics foam less and the marking is more homogeneous. Other plastics require more energy to heat up the material sufficiently. In this case, the long pulses help to optimize the foaming of the material. In both cases, marking with the MOPA laser leads to a more clear contrast and therefore to better (machine) readability. 

Foaming

Foaming is a process which leaves a tangible mark on the material. It can be seen as laser-induced boiling, which melts the surface of the material. Due to rapid cooling bubbles are encapsulated in the material which leaves a positive, tangible mark.
When laser marking with this process the laser works on a low power level with longer pulses. Foaming works on all polymers and on some metals. The selected material determines whether the mark is light or dark.

Carbonising

Carbonising is used to create strong contrasts on bright surfaces. During the carbonising process the laser heats up the surface material material (minimum 100° C) and oxygen, hydrogen or a combination of both gases is emitted. What's left is a darkened area with higher carbon concentration.
The laser works with lower energy, which leads to slightly longer processing with a laser marking machine compared to other methods. Carbonising can be used for polymers or bio-polymers such as wood or leather. Carbonising always produces a dark mark, meaning that the contrast achieved on dark materials will be minimal.

Colour change

Colour change in the material guarantees the highest legibility. Laser marking with colour change is essentially an electrical process, which reorders the macromolecules (by changing the direction). No material is removed during this process but partial foaming is possible.
The laser works with a maximum pulse rate and low energy per pulse as otherwise material would be removed or foaming might occur. Colour change works on all polymers and the change of colour can be bright or dark, however most are dark.

Removing

Removing is a process used with multilayer plastics (laminates). When using the removal process in laser marking the laser beam removes the top layers, which had been applied to the base material. This results in contrasting colours due to the colour differences in the layers.