Coating

Pore-free and crack-free layers with a long lifetime - high surface quality - exceptional durability

The process

Laser cladding generates coatings with lifetime sometimes even longer than the durability of galvanic coatings. Laser cladding is realized either as wire or powder cladding. The laser beam creates a molten pool at the workpiece surface, to which is simultaneously added the coating material (wire or powder) molten by the laser. The exposure time is short and creates only a short delay, as the cooling is quick. The result is a layer that is connected with the basic material metallurgically. It is tougher than the coatings created by thermal spraying, and compared to hard chromium plating for example, it is harmless to health. 

The process advantages of the diode lasers

The characteristices and the top-heat beam profile of the diode laser create a particularly even molten pool, which produces fine-grained, pore-free and crack-free coatings. Post-processing is thus reduced to a minimum. Integrated into systems for the extreme high-speed developed by Fraunhofer ILT, they can also be used to create very thin coatings, which hitherto could only be realized by hard chromium plating.

Advantages at a glance

  • low exposure time and depths of the laser
  • metallurgic connection of coating material and basic material
  • layers that are more constant than thermal sprayed coatings  
  • high surface quality and low delay, hardly any post-processing necessary
  • short processing times, high energy efficiency 

Application examples

Source: Technogenia

Drilling tools

The development of oil and gas fields requires high-performing drilling tools. These are subjected to huge stress and would not reach long lifetimes without wear protection. This is why special coatings, that are more and more frequently realized with laser cladding, have become the standard for some time now. Here, Laserline's LDF and LDM diode lasers have obtained very good results: their very even and calm molten pool prevents deformations of the basic material and creates high-quality coatings with excellent adhesion. Conventional hard plating methods, e.g. plasma powder cladding, do not gain sufficiently long lifetimes.

For customers engaged in oil extraction, mining, metal and paper industries, Technolgenia coats with the help of Laserline's diode laser components with a special tungsten carbide powder. 

Source: Oerlikon Metco

Agricultural machinery

The typical carbide layers meant to protect saw-blades, disc harrows or counter blades from wear and corrosion can be optimally realized with the help of Laserline’s diode lasers. Their calm molten pool leaves no impurities, and thanks to the superficial heat exposure, there is no delay to worry about. Iron carbide layers are possible, just as layers out of tungsten- or chromium-carbide.

Source: Fraunhofer ILT

High-speed cladding instead of hard chromium plating

As the most successful coating method up to now, hard chromium plating is threatened by an EU-wide prohibition, such that the industry is searching for alternatives. Hitherto, laser-based cladding seemed unsuitable because the process was too slow and did not allow for sufficiently thin coatings. However, the Fraunhofer Institute for Laser Technology (ILT) has developed a patented method, which enables high processing speeds as well as low layer thicknesses: the extreme high-speed laser cladding (EHLA). Initially, the method was only designed for coating rotationally symmetric components, but is also supposed to be available for coating other components in future.Laserline's high power diode lasers are successfully used in high speed cladding applications.