Adaptive Machining of Gas Turbine Components

Abstract

Whether to repair or replace gas turbine components has always been an issue. The case for repair has always been viewed with skepticism, especially when those parts to be repaired must be done by hand, as manual repair methods can result in high levels of scrap and non-conformance. Hand grinding, blending and polishing is still frequently found in many Gas Turbine (GT) components, but in this age of high technology, why is this the case? The problem lies with the fact that individual blades and vanes that make up full engine sets are not geometrically identical and do not lend themselves to being machined, blended or polished by standard Computer Numerical Controlled (CNC) machining technology. This is a problem for both the repair and manufacture sectors. Key Questions: • Where does this geometric variability come from and what does this mean in practice? • As the industry strives for more efficient engines blades and vanes have become increasingly complex. How does this impact the repair sector? • What are the key issues involved and how can we get around them? • What can repairers do to reduce their scrap rates and increase their output volume and quality? Software-based machining strategies are explored as an alternative to manual processes in the repair of GT components. With ever-increasing competition and reduced turnaround times, decisions to invest in technology are usually driven by a combination of technical, quality, economic and health & safety requirements.