Advances in the Grinding of Aerospace Engine Materials

Many aerospace components used in the high and low pressure sections of a turbine engine are made from materials such as high nickel-based super alloys and or intermetallics such as gamma titanium aluminide. These sections that may be cast, forged or sintered using powder metallurgy techniques, are notorious for being difficult to machine due to their high strength, corrosion and fatigue resistance, and low thermal conductivity. Many of these components have as much as two-thirds of their original weight to be removed to produce the finished component. Traditionally turning, milling and broaching processes are employed to remove most or all of the material from these components. However, with the use of modern grinding wheels composed of engineered grains and high strength bond technology, it has been determined that for these material types, grinding can remove the material more quickly and economically than turning or milling. This presentation will show data/results of the surface grinding and creep feed grinding tests done on grinding of these advanced aerospace engine materials such as gamma titanium aluminide and IN718 with conventional abrasive grinding wheels as well superabrasive grinding wheels. Additionaly, the growth in robotic manufacturing is driving the development of abrasive products that are custom-made for robotic material removal.  This presentation will also show data/results from fixed abrasive polishing of contoured IN718 parts with engineered abrasive belts for robotic turbine-blade-polishing applications.