‘Plastics’ refer to materials with widely differing chemical compositions, which in turn means differing outcomes for the processes applied to them, including laser marking. Indeed, among plastics we can distinguish between polycarbonate, polyamide, polyester, PE, PET, ABS, and many others. These influence the choice of laser in terms of required wavelength.

By way of example, PET requires a specific short wavelength (9.3 μm) obtainable with CO2 laser markers. A laser with a different wavelength would risk overheating the plastic, causing micro-holes and burns. Laser marking on this quasi-transparent plastic results in white characters that seem to float on the surface. From PET bottles to thin film materials, laser markings with the correct parameters are always clear and sharp.

The different laser sources and the extensive specialization of modern laser technology currently allow us to mark all types of plastics, although the reactions due to color pigments and other additives vary widely.

Laser marking is preferable to other technologies for placing codes, logos, and designs on plastic components. Compared to ink-jet, laser marking does not have the problem of ink adhesion, dark substrate contrast, or finish complexity.

This is because the laser removes or modifies the surface of the plastic material, or modifies its color, creating a contrast.

The most popular lasers for plastic applications are the well-known UV laser, the FlyPeak green wave laser from LASIT, and the traditional green light laser with a fiber optic source. In most cases we recommend using a MOPA laser, meaning with variable pulse: thanks to the pulse duration control, this laser ensures maximum performance on more difficult applications.

Laser technicians carry out tests to determine which laser is best suited to achieve the desired result on specific plastics. The initial parameters used are usually those listed below. Starting from the results of the first tests, it is possible to identify the parameters best suited to the specific processing desired.