Lufthansa Technik AG has filed patent applications for a new scarf joining robot that it says will significantly improve repair procedures for structures made of fiber-reinforced composites (FRCs). The robot, which was developed through LHT's Composite Adaptable Inspection and Repair (CAIRE) project, is mounted on an aircraft component using suction cups. The robot's specially developed software scans and diagnoses damage, identifies the surface and calculates the scarf joint's form and a milling path before cutting out the damaged material. Once this is complete, technicians can cut repair layers to size, insert them into the 3D scarfing surface the robot created and finish by gluing and curing the newly inserted part.
The traditional process for diagnosing and repairing damage to FRC-based fuselage and wing structures requires more time and effort than the new automated process, so LHT says targeted use of the robot will result in time and cost savings. The company also claims the robot will significantly increase quality by allowing for brand new repair geometries.
"Thanks to the positioning mechanism, employees can precisely position the scarf joining robot anywhere on the aircraft without anyone else's assistance—whether from the side, from above with an overhead crane or even upside down with the help of hoisting gear. The increases in accuracy go far beyond what is possible with other industrial robots," says Dr. Henrik Schmutzler, project manager for CAIRE.
LHT says the robot successfully passed all testing during development, including trials on individual components and entire aircraft. The company says testing has proven the robot's ability to complete adhesive-based repairs on critical FRC structures and allow for reproducible damage repairs.
According to LHT, the robot will be coming to commercial operations in the fall of 2018. The first CAIRE robotic system will be used by the MRO's Airframe Related Components (ARC) unit for structural components. For now, LHT plans to keep the new technology in-house, although a spokesperson says the company is open to discussing other business models.
Other related robotics and automation projects recently completed by LHT include AutoInspect—which resulted in automating the inspection process for engine components into a single step—and AutoRep—which integrated robots in the process chain for repairing engine components.