Method set to cut scrap rates of aero-engine turbine blades

UK-based Metrology Software Products (MSP) and Hong Kong Polytechnic University have developed and tested a way of fully automating the machine tooling process, thereby improving accuracy.

Maintenance company Hong Kong Aero Engines (HAESL), a joint venture with Rolls-Royce, now plans to start using the method in its turbine blade refurbishment programme later in the year.

Aero-engine turbine blades are subjected to extreme temperatures during operation, resulting in deformation and distortion over time.

After a period of around 30,000 hours of air time, engines are entirely overhauled and the blades are taken out and repaired where possible, through metal deposition and machine tooling.

‘The major problem we identified was that many parts were being machined incorrectly because they were not located on the machine tool at the position they were supposed to be, through errors in fixturing or in built-up tolerances,’ said Peter Hammond, managing director of MSP.

Around half of blades are, in theory, reclaimable, although the current yield is only around 80 per cent of that half owing to avoidable errors and poor practice, according to MSP. The company claimed it could increase that to a near-100 per cent level. To achieve this, it worked with Hong Kong Polytechnic University and came up with a patented software system, called NC-PerfectPart.