Optimization of Serrated End Mills for Reduced Cutting Energy and Higher Stability

Abstract

Although serrated end mills are commonly used in machining industry, the literature on these tools is limited to predictive methods while no work has been reported on selection, design or optimization of serration forms. In this paper, mechanics and dynamics of these tools are modeled and experimentally verified. Linear edge-force model is adopted for force modeling whereas first order semi-discretization method including multiple delays with time-averaged coefficient matrices is used for stability analysis. Frequently used serration waveforms, i.e. sinusoidal, circular and trapezoidal are modeled parametrically and optimized for reduced milling forces using the Brute Force Search and the Differential Evolution Method. The superior performance of the optimized serrated end mills is demonstrated in terms of reduced milling forces and increased stability.