Coating of wind turbine plain bearings

Laser-based cladding increases service life and allows process speeds to be increased

The coating of plain bearings plays a key role: It reduces frictional resistance and thus increases the service life of the components. So far, wind turbine plain bearings have mostly been coated using the centrifugal casting process or oven coating. However, these processes have some weaknesses: They are energy intensive and often based on combustion of natural gas and require a significant amount of material to achieve high-quality results. Meanwhile, laser cladding turned out to become an alternative: It not only impresses with lower energy and material consumption, but also with higher robustness, thinner, well-defined, and lead-free coatings of the highest quality.

 

These results are made possible by the use of high-performance processes that minimize the heat input into the workpiece. For wind turbine plain bearings, non-ferrous metals and copper-tin alloys are commonly used to coat the outer diameter - i.e. the shaft - and are applied in a single-stage process at process speeds of several meters per minute. This creates a durable and robust bonding between the base material and the coating materials. A key advantage of laser cladding is its flexibility, which allows, for example, to adjust the spot size and geometry as well as the laser power to customer’s requirements.