Surface topography modeling and roughness extraction in helical milling operation

As a new hole-making method, helical milling has been widely used to machine holes on difficult-to-cut materials in the aircraft industry. The accurate prediction of the surface topography and the corresponding surface roughness are essential for optimizing the cutting conditions in order to improve the surface quality of the generated holes. In this paper, the kinematics of helical milling was first analyzed. Subsequently, a mathematical model was established to simulate the three-dimensional surface topography after a helical milling operation, in which the tool eccentricity, the secondary cutting, and also the size effect were taken into account. Further, an in-depth research on the process of extracting surface roughness from the surface topography was conducted. The proposed method is capable of extracting the roughness of the generated hole effectively, and meanwhile the predicted surface roughness is well in harmony with the experimental result. As a result, the developed model in this work can be used in planning and optimizing the cutting conditions.