Laser marking by Keune & Lauber – precise, flexible and durable
The use of a laser as a tool for marking and inscribing during plastic processing is indispensable nowadays. The automotive industry, the “white goods” sector and electrical technology industry are just a few of the many industries in which laser marking is the preferred method of inscription. With the help of laser inscription, it is possible for us to give your parts and components a precise and durable marking. We can also inscribe complex parts in uneven or difficult to reach areas with the laser. Our laser processing systems have advanced control systems. Extensive options ensure a best-possible parameter optimization and the professional implementation of your ideas and wishes.
Marking with light – advantages of laser inscription
Inscription lasers are the most reliable system for adding information to plastic parts. Unlike many other inscription processes, laser marking is durable and forgery-proof. Here at Keune&Lauber, we primarily laser letterings and symbols. During this process, the laser removes the paint leaving the plastic beneath visible. As the laser rays can be focused very precisely, it is possible to focus in on the smallest areas. The entire marking process is done contact-free so that the component or part is not subject to any mechanical strain. As the intensely focused light is not opposed by any mechanical resistance, it is possible to achieve high processing speeds. In addition, laser markings are not sensitive to abrasion, environmental influences and solvents.
All the advantages of laser marking at a glance:
- No pre- or post-handling is required,
- Very narrow line widths can be achieved,
- Quicker and more flexible than mechanical processes,
- Water and smear-resistant,
- Holds under thermal and chemical strain for the entire service life of the product,
- High-contrast labeling,
- Low influence on the material,
- Works with any material geometry.
Laser inscription offers particular advantages if the product needs to be inscribed with variable letters or symbols. These datasets can be easily prepared via the appropriate software interfaces and integrated into the inscription process.
Operating principles of the laser marking
The word laser is an acronym for "light amplification by stimulated emission of radiation”. Within the laser marker, there is an active medium (laser medium), which emits energy in the form of light as long as energy is pumped in via an external pump. The resulting light radiation is amplified by a resonator. In the simplest case, this resonator consists of two parallel mirrors, one of which is semipermeable and the other of which is impermeable to light. The light waves produced are reflected back and forth between these mirrors until they escape from the semipermeable mirror as a bundled laser beam and can be used.
Different types of laser markings of plastics
Plastics are commonly made up of different original materials which react differently when processed with a laser. But here, it’s not just the material itself that plays a role. Individual color pigments or additional mixing components such as additives, fillers or protective substances can affect the laser result. There are different methods which can be used to inscribe plastic parts with a laser. The laser method used depends on the plastic used, the special requirements regarding the inscription and finally the laser wavelength. In particular, the following methods are used at Keune & Lauber GmbH:
Laser engraving
With the laser engraving of plastics, material from the surface of the part is removed, analogous to metal engraving. This results in a deepening, similar to what happens with mechanical engraving. The component is not heated up during this process. Only the material in the area that is being inscribed is superficially melted and vaporized. Due to the low thermal conductivity of the plastic, the amount of material which is melted is low. The material transforms directly from a solid to a gas. The maximum engraving depth and speed is determined by the material and the performance level of the laser. As a general rule, surface laser engraving is quicker than deep engraving. In addition, the engraving process on low density materials does not last as long as on materials which have a higher density. For the laser engraving of non-metallic materials such as plastics, a carbon dioxide laser with a wavelength of 10.6 µm is mainly used. This type of laser is less suitable for metals as their smooth surface would reflect the majority of the laser energy.
Removing a cover layer
Multi-layer plastics can be inscribed by removing a thin surface layer, such as a layer of paintwork. For an optimal laser process step, the layer must have the following characteristics:
- High contrast to the carrier material,
- Very homogeneous layer thickness,
- Good absorption capacity for the wavelength of the laser.
It is mostly translucent plastics, which are then painted in the desired shade, that work as a carrier. The laser marking is then “burnt off” of the paint surfaces. By doing this, the laser inscription is made visible as the deeper layers differ in color from the cover layer. In this way, the lettering can be done in both dark and light colors. This form of laser marking has been used in the automotive industry to make operating elements with a day/night design since the end of the 1980’s. The advantages of this type of laser processing lie in the very short preparation times needed for any modifications made to the symbols used, as well as in the robust nature of the laser inscription. Color removal with the laser is the most reliable and sensible inscription option.
Diverse application possibilities for the laser inscription of plastics
The various different laser processes and wide range of plastics which can be inscribed result in an extensive spectrum of applications for laser marking. Many fields of applications can be found in the automotive, electrical technology, household appliances, machine construction, food and medical technology industries. Specific applications for laser marking include:
- Day/night design elements,
- Marking of casing parts.
Whether it be writing, graphics, logos, bar codes or other information – Keune & Lauber can perform individual, durable laser markings through engraving or color removal. We can also use different fonts, different sizes and symbols, as well as different depths and line widths. You can rely on our know-how.