Gas turbine engines are complex pieces of machinery which, generally speaking, have a compressor to compress and direct air to a combustor, where the air is then mixed with a fuel and ignited, and the resulting combustion gases are then passed through a turbine. To capture the moving air and turn same into rotational energy, the compressor and turbine have a plurality of airfoils in the form of radially outwardly extending blades, and radially inwardly extending vanes.
As engine designs have evolved, the materials from which those airfoils are manufactured, as well as their shape and curvature have become increasingly important. Not only must the airfoils be strong, but they must be able to withstand extreme temperature ranges and be as light weight as possible. They must also be aerodynamically smooth. In order to achieve such an aerodynamic surface, airfoils are typically processed through a vibratory media finishing procedure, such as a drag finishing procedure, to polish and remove metals from the surface of the airfoils. In particular, the a cluster of airfoils is often held by spindles or arms of a drag finishing mechanism and driven and/or spun through a bath of abrasive media at a rate sufficient to provide a finished surface thereon.
Current finishing processes, however, often result in inconsistent finishes among the airfoils, where the airfoils located at the outermost ends of the cluster exhibit a significantly higher rate of wear than the inner airfoils. This is due to the substantially free stream of abrasive media passing at the outermost ends of the cluster, in contrast to the more restricted stream of media passing through the inner airfoils of the cluster.
Such inconsistencies not only cause significant losses in engine efficiency and performance, but also weaken the integrity of the outermost airfoils making them more prone to damage over time. Accordingly, there is a need to provide improved and more consistent apparatus and method for media finishing sensitive metals, such as airfoils. The present disclosure aims to overcome one or more of the deficiencies set forth above.