Airfoil repair requires the filling of cracks and checks with new metal or the replacement of missing airfoil sections with new stock. Typically, the repair location has a bead of metal at the seam which must be blended into the airfoil geometry to achieve the final profile. Additionally, high temperature engine oxide contaminated airfoils are submitted for overhaul work, frequently in a pitted, pockmarked condition. Pits and pockmarks must be blended into the airfoil geometry to achieve the final finish. Traditionally, airfoil surface geometry is obtained by repetitive polishing with increasingly finer abrasive belts to obtain an airflow efficient surface finish of approx= 20 #mu#inches; Nebiolo, 1996. The process works well but is repetitive, time consuming, labor intensive and dependent upon the skill level of the polisher. Multiple belting operations usually result in cuts beneath the deepest airfoil surface pit resulting in excessive metal removal and the alteration of airfoil chord and thickness dimensions. This can effectively reduce the number of overhaul cycles possible for the airfoil. This paper will compare chemically accelerated vibratory finishing vs traditional hand belting procedures and standard vibratory finishing as a technique to achieve an appropriate airfoil surface whileminimizing overall metal removal.
展开▼
