Researchers have developed a laser-based method to repair the landing gear of an aircraft, the highly stressed parts of a plane.During takeoff, landing, and taxiing, components such as wheel axles, shock-absorbing pistons, and connecting pins endure massive forces. At the same time, bearings, bushings, and seals are subjected to constant friction and wear.Moreover, repeated exposure to cold, heat, moisture, kerosene, cleaning and deicing agents, as well as ice, sand and dust make these aircraft surfaces more vulnerable to corrosion.Minor damage is scraped off from the material during the routine maintenance; however, this approach can be used only up to a certain limit. Beyond that, this replacing a part is the only option, which is not only expensive but keeps the aircraft out of service for longer periods.High-speed lasers for aerospace repairTraditionally, chromium plating has been used to protect surfaces; however, environmental and occupational safety concerns have pushed scientists to look for alternatives.Welding parts is not a viable alternative, as excessive heat could alter the microstructure of aerospace steels and change the component geometry. To counter these challenges, scientists at the Fraunhofer Institute for Laser Technology ILT in Germany have devised a high-speed variant of laser metal deposition (LMD).Extreme High-Speed Laser Material Deposition (EHLA) is a faster version of LMD that uses a laser to melt metal powder and apply it precisely where needed. The process works much faster than conventional methods while generating less heat. This makes it suitable for repairing or coating heat-sensitive, high-strength aerospace components.The researchers turned to this modified approach that world work in real-world scenarios and beyond the laboratories.”What matters is whether the process is suitable for real landing gear components under load, including their materials, damage patterns and repair limits,” said Harald Betsch of Liebherr-Aerospace, Senior Expert Thermal Spraying/Welding in Materials and Processes.Hard-press rollers for finishShortly after the laser-assisted metal deposition, the team presses a hard roller against the material rather than cutting or grinding it, a process done in a single step. The researchers called it Simultaneous Coating and Roller Burnishing (SCaRB).”The key for us is to use the layer while it is still warm, rather than finishing the EHLA coating in a separate operation afterward,” explained Kim Julia Kallies, project manager at Fraunhofer ILT.By smoothing and strengthening the freshly deposited, still-warm metal layer, it eliminates separate finishing steps, reduces setup time, and allows researchers to tailor surface finish, hardness, and residual stresses for repaired aircraft components.Researchers noted that they can tune the repaired area’s hardness, surface finish, and residual stresses by adjusting process parameters, including laser power, powder feed, distance between laser and burnishing tool, burnishing force, roller radius, and hardness.The technology is still being validated by researchers by testing the material’s durability under realistic conditions.Beyond the repair process, the team used a laser to check coating and subsurface quality without damaging the repaired part. The method, LAwave (short for laser-induced surface acoustic wave spectroscopy), generates acoustic (sound) waves and analyzes how they travel through the material.However, the method still requires further development to qualify for aerospace standards, as the researchers are currently testing it on real landing gear geometries under representative loads.