Flow line machining of turbine blades

Abstract

Flow line machining is a new method to mill free- form surfaces with tool paths that reflect the nature shapes of surfaces. High efficiency machining of turbine blades requires the two sides of the blade to be milled together from top to bottom continuously. Currently available CAD/CAM systems in market have the functions to provide flow line tool paths, but are unable to process complicated surfaces, for example, to mill the whole blade which are trimmed surfaces iin once. This paper introduces the implementation of a new tool path generation algorithm - boundary conformed tool path generation in milling of blade surfaces. With this method, The lirst segment of tool paths is along the top edge of the blade while the end one follows the intersection curve between the blade and the hub surface, those in,between cover the surface by "morplhing" smoothly from the start tool path to the end one, the two siides of the blade are machined together from top to bottom with boundary conformed flow line tool paths. This method has been successfully integrated into a commercial CAD/CAM system, ProlEngineer. Detailed algorithm and implementation processes have been introduced.