- Based on pulsed ytterbium fiber laser technology
- Wide range of materials consisting of aluminum, steel, plastic, and films
- Direct laser marking means: No inks, no ink ribbon, no toner
- Permanent marking via engraving, annealing, or carbonization
- High quality: can print bar codes, 500 dpi resolution
Marking principle – laser technology
During laser marking, a focused laser beam is guided over the component to be marked. Depending on the material, there are various options for creating the contrast required with the base material.
As laser markings are made directly in the base material, they are very resistant. Individually adjusting the parameters to the material is crucial. Not all materials are suitable for laser marking.
When it comes to engraving, a distinction is made between two variants: Engraving solid material and engraving through abrasion of the top coating. Both processes are based on powerful laser pulses, which are so strong that the material melts and vaporizes.
Engraving solid material
When engraving solid material, the laser beam creates an indentation – the engraving.
Engraving through abrasion of the top coating
Through abrasion of the top coating, the base material becomes visible. For this process, anodized aluminum, coating layers, or special laser marking films are generally used. This creates a contrast, with the materials underneath becoming visible.
In annealing marking, the laser applies an oxide layer in the workpiece. The color of the layer depends on the temperature. No material is removed in this case; the surface of the workpiece remains smooth and even.
Carbonization causes the material to darken. This process can be used for light plastics and different organic materials, such as wood, leather, or paper.
During foaming, the laser beam not only warms the material, but also melts it. In the molten mass, a plastic foam which contains small gas bubbles develops. This means the light reflection changes and allows the processed area to appear much brighter and higher. As such, dark plastics can be colored white in targeted areas.
Further processing: Cutting
After laser marking, different contoured shapes can be individually created by means of laser cutting. The laser continuously removes the material along the desired contour and completely separates the parts.
Lasers are divided into two operating modes:
- Continuous beam lasers emit a constant light wave of the same intensity
- Pulse lasers generate a pulsing beam and are divided according to the temporal duration of the pulses into short or ultra-short pulse lasers
Lasers are specified based on the medium used: Solid state and gas lasers. The active medium in solid-state lasers is doped glass or crystal. Foreign ions are included in a range of concentrations in the host crystal. These ions are available in a specified doping level (concentration). Typical doping materials are neodymium, ytterbium, titanium, and erbium.
The fiber laser is one of the solid-state lasers and, due to its compact design and ease of maintenance, is particularly well-suited to marking. A typical fiber laser is the ytterbium-yttrium-aluminum-garnet laser.
Ytterbium-yttrium-aluminum-garnet lasers emit infrared radiation, so that the laser beam can be directed through fiberglass cables in contrast to CO2 laser beams. Due to the short wavelength, these lasers can be focused on a smaller surface, thereby achieving a higher resolution than a CO2 laser.
When working with lasers, dust and gases can be generated. These must be removed from the processing room to ensure that a consistently high level of quality is maintained. Extraction that suits the respective application is also necessary for occupational health reasons. Using a combination of different filter classes is recommended to ensure the highest possible degree of extraction. Filters are differentiated based on the particle size:
- Coarse particle filter (>10 µm particles)
- Fine particle filter (1 to 10 µm particles)
- HEPA filter (<1 µm particles)
In an ideal scenario, the air from the processing room is pre-filtered first using different fine particle filters. Then, in a second step, the smallest particles are also filtered from the air using a HEPA filter. In this way, an overall separation efficiency of over 99.9% can be achieved.