Investigating the asymmetricity of indexable tool bodies for better chatter resistance

Official URL: https://www.utis.tc/gorseller/files/UTIS%202024_Proceedings.pdf

Milling operations are often limited by regenerative vibrations arising due to the flexible machine tool parts which have dynamic effects on both stationary and rotary directions. Additionally, asymmetricity of the milling cutter has an impact on the rotating dynamics of the machine tool. However, asymmetric tools 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; these tools have less coupled stiffness and mass characteristics and thus would be more suitable for dynamic tuning. It is shown that the stability lobes diagram is quite sensitive to the degree of asymmetricity of the end mill. Also, it may not be straightforward to predict the frequency response function of the tool, mainly due to the contact parameters of between tool and holder. Therefore, in the future studies, a dedicated structural model is required to decide the required stiffness and mass of the end mill for better chatter resistance.