An oscillating milling strategy based on the uniform wear theory for improving service life of the ball-end cutter

Rapid wear of ball-end cutters results in short service life when milling difficult-to-cut materials, such as titanium and Ni-based superalloys. In this study, an oscillating milling strategy was proposed which attempted to improve uniform wear degree of the cutting edge by making full use of the wear overlap regions, thus extending service life of the ball-end cutter. Firstly, the cutting edge was divided into several cutting units(CUs) and the equal linear speed was used as a criterion for establishing cutting parameters. Subsequently, the tool wear model was established to describe the wear resistance of CUs along the cutting edge. Based on it, an optimization model for the oscillating milling strategy based on uniform wear theory was developed. Cutting tasks for different CUs were assigned according to the optimization model and were executed sequentially by oscillating cutting. Cutting experiments were carried out on both planar and free-form surfaces of Ni-based superalloy GH4169/ Ni718. Results showed that the machining strategy significantly increased tool service life by increasing the uniform wear degree of the cutting edge, in addition to improving the surface consistency of the workpiece.