Compressor and turbine blades are important components in aircraft engines and gas turbines. When they become damaged, it is often cheaper to repair them than to buy replacements. Now there is a new robot-assisted technique that is boosting efficiency.
The German turbomachinery sector is booming. Over the past 25 years, it has doubled its share of the global market from 15 to 30 percent. For manufacturers, the service business – i.e. maintenance, repair, and overhaul (MRO) – is steadily growing in importance. The blades in compressors and turbines are subject to particularly high levels of stress and strain. The job of the blades is to convert fluid energy into mechanical energy. They ensure that aircraft engines generate the required thrust and that power plant generators produce sufficient electricity.
“Damage to the blades of aircraft turbines is caused by wear from vibration and friction, for example, or by erosion from particles of sand and dust. Other triggers are hard landings, when individual engine components come into contact with each other, and large objects striking the engine,” explains Martin Bilz, head of manufacturing technologies at the Fraunhofer Institute for Production Systems and Design Technology IPK in Berlin. In such cases, the geometrically complex components, which are mostly made of titanium- or nickel-alloy steels, bend or crack and the flow of air is no longer optimal. This can cause engine performance to drop and fuel consumption to rise.
Time-consuming manual labor
Repairing the damaged components makes sound financial sense. Depending on the stage and engine size, a single turbine blade can cost several thousand euros. With an airplane needing up to 80 blades, the costs stack up very quickly for aircraft operators. Repair, however, is over 50% cheaper. The drawback with repair is that the processes involved are very complicated and elaborate. The individual work steps cannot be easily integrated into largely automated series manufacturing. Specialists process the workpieces by hand or with specially adapted machine tools. Depending on its size, it can take anything from a few hours to several days before a single blade is repaired. Or to give another example: on account of the strict quality assurance requirements in the aviation industry, it can often take two to three weeks before an individual rotating engine component can return to action.
Read more at: Phys.org