About laser marking

Laser marking is fundamentally different from ink printing, the traditional method of writing on plastics. Whereas direct ink printing puts an image on the surface of the plastic, laser marking can provide an indelible, high-contrast mark under the surface. With laser marking, there is no direct contact with the plastic other than through the laser beam.

Laser marking is the most flexible way of marking plastics and yields legible, sharp and indelible images. Lasers can mark products with various geometries in a fully computer-controlled process with high reproducibility and reliability. What’s more, laser marking can be integrated in-line at the end of the assembly line as well as offline (or standalone), resulting in flexibility in marking and logistics. Combined with reject rates well below 0.01%, this leads to cost reduction in most cases.

Laser light is light of a single wavelength, with high energy, that interacts with a material to provide it with a mark. The development of lasers is an ongoing process. The available lasers are computer-controlled industrial laser systems, which can be integrated into fully automated production lines: 

Nd:YAG lasers (Neodymium-doped Y3Al5O12:Yttrium-Aluminium Garnet) or Nd:YVO4 lasers (Neodymium-doped YVO4:Yttrium-Vanadium-Oxide), operate at three available wavelengths: 1064 nm (the “red” laser), 532 nm (frequency-doubled: the “green” laser) and 355 nm (frequency tripled: UV-laser). Depending on the wavelength the chemical reaction is either heat induced (such as foaming) or based upon photochemistry (a photochemical reaction). More information about these lasers is available via our Links page.

Excimer lasers, operating at several available wavelengths between 170 nm and 351 nm depending on the working gas used) are mainly used for photochemical reactions (such as photo reduction). Heat induced reactions such as high precision ablation are also possible. More information about these lasers is available via our Links page.

In general two techniques can be distinguished: mask marking and marking by means of galvanic mirrors. Mask marking is preferred where high production rates are required in large series. Marking by means of galvanic mirrors is preferred when production flexibility and high-image quality are required.

Laser light and polymer material can interact in various ways:
· Engraving
· Ablation
· Foaming
· Carbonization
· Photo reduction