Lufthansa Technik is developing automated inspection and repair techniques for engine components, in an effort to raise productivity versus traditional manual processes.
Together with Hamburg's technical university, research organisation Fraunhofer and industrial partners, the MRO group has developed a robot to examine the outer liner of combustors on CFM International CFM56 engines, under a project dubbed "AutoInspect".
But the technology could be a "door opener" to deployment of robots for inspection of other powerplant components, such as fan blades, casings and aerofoils in both the compressor and turbine, says project manager Michael Ernst.
White-light interferometry is applied in the fully automated process. The partners have adapted the long-established measuring method for component inspections in an initial research project that began in 2011.
The MRO provider has since installed a robotic unit at its Hamburg headquarters as part of an industrialisation phase. Inspection times for combustor liners could be reduced from an average of four work shifts – over two days – to less than 4h, says Ernst.
Handling enormous data volumes has been a challenge in using white-light interferometry in the past, as the method generates around 130,000 images during the inspection of a combustor liner. But this has been overcome with increasing computer performance. The system detect irregularities with lateral dimensions down to 20μm and depths of 100nm.
Enabling the robot to differentiate between surface scratches and micro-cracks has been another challenge, says Ernst. But programming such software has helped to categorise signs of damage more clearly and determine whether or not defects require repairs, says Ernst. During manual inspections, that assessment depends on technicians' individual experience.
In 2012, the research partners started a parallel project dubbed "AutoRepair" project, under which Lufthansa Technik is now preparing to install another robot to conduct fully automated repairs.
A two-year industrial trial is begin in the fourth quarter of 2015, says team leader Thiemo Ullrich. It is not yet decided whether that set-up will comprise separate milling and welding robots or a combined unit with different tooling, or utilise an existing CNC facility at the MRO specialist. The project mainly concerns development of software rather than tooling machinery, says Ullrich.
While regular aircraft components are still inspected and repaired using traditional manual processes, robots are used as part of an industrial assessment. But the technology promises to reduce average turnaround times for combustor liners from 25 days to 20, says Ullrich. Other benefits include increased process reliability, 24/7 operation, and environmental gains, as the use of dyes for fluorescent penetrant inspections is reduced.
The next stage is to include high-pressure compressor casings in the trial, says Ernst.
Source: Cirium Dashboard
