On monitoring chip formation, penetration depth and cutting malfunctions in bone micro-drilling via acoustic emission

Micro-drilling of bone is increasing demanded in many kinds of surgery operations recently. One of the mainly challenges in this procedure is to control the drilling process and avoid the surrounding tissue damage. Monitoring the cutting condition is expected to be a promising way for safety enhancement and application of automated solution for robot surgery. However, there is still no efficient method to meet this issue. The present paper reports on the possibility of using AE sensory measure for monitoring bone cutting process and support the understanding of the cutting phenomena on this unique material. For this purpose, the main frequency band of AE signal in bone micro-drilling was studied. Chip formation analysis was carried out to capture the relationship between AE signal and the chip morphology in bone micro-drilling process. A wavelet based approach was proposed to detect the penetration position of the micro drill and cutting malfunctions in micro-drilling process combined with the fractal analysis. The experimental results with micro-drilling of bovine rib bone showed good evidence that the proposed AE sensory measures have a great potential to be used in efficient and easily implementable solutions for monitoring the bone micro-drilling process.