Asymmetric indexable cutter bodies for better chatter resistance

Milling operations are often limited by regenerative chatter vibrations arising due to the flexible machine tool parts which have dynamic effects on both stationary and rotary directions. Additionally, asymmetricity (or, non-axisymmetricity) of the milling cutter has an impact on rotating dynamics of the machine tool. However, asymmetric cutters may not always have positive effects hence care must be taken when using them. This paper investigates how to achieve desired chatter stability characteristics by tuning the dynamic response of the tool body. Both frequency and time domain methods were used to predict the stability lobes diagram according to the measured tool tip frequency response functions. An indexable end mill with exchangeable head is used for demonstration of dynamic tuning. Additionally, receptance coupling substructure analysis is used to predict the tool tip frequency response function for various degrees of asymmetry. The milling tests validated that the proposed approach captures the sensitivity of the stability lobes diagram to the degree of asymmetricity. The highest degree of asymmetricity had an unacceptable reduction in stability, while the suggested degree moves the stability pocket below the maximum spindle speed while keeping similar stable depth of cut.