Summary
The occurrence of dynamic high-amplitude chatter vibrations in high-speed micro-drills used for delicate neural, orthopaedic, and otolaryngology surgical procedures are investigated through experimental modal analysis. Traditional modal analysis techniques are unsuitable for the small geometry of this drill, requiring alternative excitation and data acquisition methods. The effectiveness of non-contact measurement techniques such as laser doppler vibrometers, high speed cameras and microphones are explored to collect vibration data. Parallelly, alternative methods of excitation to excite the higher frequency bandwidths at which these micro-drills operate are investigated. This study aims to extract the natural frequencies, damping coefficients and mode shapes. With a better understanding of these dynamical characteristics, an equivalent dynamical model that could capture regenerative and friction effects could be devised to examine the machining stability of micro-drills on bone, comprehend the origins of instability, thereby minimizing chatter and large amplitude vibrations. This could ultimately enhance the safety of surgeries and improve patient outcomes. Subsequent experiments will delve into investigating the dynamic behaviours of the drill under cutting conditions to replicate real surgical scenarios.
