Motion control solution for aircraft turbo fan engine blade maintenance

Very often the company is called upon to provide a solution for a very particular and almost unique requirement which requires close collaboration between the team of engineers at LG Motion and the equipment supplier and end user.

Project to optimise maintenance of turbo fan engines

LG Motion’s client CR Solutions Ltd had been called upon by Rolls Royce to provide a system to optimise the
process of maintaining and servicing turbo fan engines.

The challenge

For maximum efficiency of an aircraft turbo fan engine the gap between the tip of the fan blades and the engine inner surface must be an optimum. Through normal wear and tear and as a consequence of repeated heavy landings when the engine might become distorted in shape, the tip of the blades can come into contact
with the inner surface thus making the gap excessively large or irregular.

Until now the inner surface of the engine had to be machined out, refitted and reground by hand, relying heavily upon the expertise and experience of the operator to achieve the right finish - rather like filling and machining out dents in car bodies.  For the aircraft operator this part of the maintenance programme is
both costly and time consuming.

The solution

To improve this process a number of assemblies have been designed and constructed which contain customised linear slides from LG Motion which are able to meet the exacting space and performance requirements for this challenging application. The equipment can be deployed in engines while still mounted on the aircraft, following removal of the blades. Now the new inner surface can
be machined using the engine rotor while turned manually. This new process allows a considerable amount of time and cost to be saved.

The complete assembly comprises a spindle motor with a grinding tool mounted on a servo-controlled leadscrew arrangement that allows the grinding tool to be controlled in the Y and Z directions. Using the engine rotor eliminates any problems of eccentricity and both the cutting depth and position can be precisely determined and maintained.