Modelling and optimisation of temperature and force behaviour in high-speed bone drilling

Abstract

Bone drilling and implantation are important in orthopaedic surgery, dentistry and also fracture treatment. In many cases, due to the rise in temperature during bone drilling (higher than 47 °C) and low conductivity of bone, thermal necrosis occurs. There is also risk of drill fracture due to the excessive thrust force. Despite many studies on the effect of different parameters on bone drilling temperature and force, there is still no clarity about the influence of the tool rotational speed and feed rate on the temperature and force responses. The aim of this study was to test and optimise the conditions in high-speed bone drilling, process force and temperature simultaneously. The results demonstrated that high-speed drilling is a suitable method for decreasing process temperature and force, and the rotational speed, feed rate and tool diameter were the most important factors in the high-speed bone drilling processes. Using a statistical method to model and optimise the process, a second-order model was developed to predict the behaviour of process temperature and thrust force in high-speed drilling. The optimised values were a rotational speed of 11778 rpm, feed rate of 50 mm/min and tool diameter of 2 mm, where the process force and temperature were 15.85 N and 33.4 °C, respectively. Therefore, in high-speed bone drilling, the process thrust force and temperature decline, and the low effect of feed rate on temperature enables an increase in the speed of operation in robotic surgery.

Keywords

• machining
• high-speed bone drilling
• design of experiment
• optimisation
• force
• temperature
• thermal osteonecrosis