Laser metal deposition (LMD) offers a number of advantages in comparison to conventional procedures like TIG (Tungsten Inert Gas) and PTA (Plasma Transferred Arc) welding as well as spraying techniques. These advantages include improved metallurgical bonding of the layer and the substrate, low heat transfer to the workpiece, and the possibility of depositing layers of varying thickness from 1/10 mm to several mm by utilizing multi-layering techniques.
The filler material is melted using the laser beam and fused with the base material. Usually the filler material is added in form of powder. The LMD process allows a high precision of the material deposition, an outstanding controllability of the process and a low thermal and mechanical load on the components. Damage or wear on turbo-engine components, machine parts, tools, molds and components can prove enormously costly. The parts affected often have to be replaced, in which case repair by LMD proves a viable option. Given the material and accuracy requirements, as well as the safety considerations associated with engine technology, LMD is an appropriate method for repair and restoration as well as for wear and corrosion protection.
Based on a three-dimensional data model of the virgin part or tool, the laser beam deposits the original material on the damaged parts using a powder feed nozzle, in a highly precise, layer-by-layer process. For the deposition of different materials and layers, suitable powder feed nozzles and highly flexible optics capable to deliver variable spot sizes are required.