Experimental measurements of temperatures in ultrasonically assisted drilling of cortical bone

Heat generation is a well-known problem in bone drilling. Excessive heat generation during drilling operation on bone causes necrosis of the tissue. This paper presents measurements and analysis of temperatures in ultrasonically assisted drilling of bone. The main objective was to find critical drilling parameters (drill speed and feed rate) and ultrasonic parameters (frequency and amplitude) for producing higher temperatures in bone. The increase in drilling speed and feed rate were found to increase the temperatures in bone. The frequencies above 15 kHz were found to produce higher temperatures in bone. The feed rates above 30 mm/min and the amplitude of vibration up to 20 mu m were found to have no significant effect on bone temperature. Ultrasonically assisted drilling may be used as an alternative to conventional drilling in orthopaedic surgical procedures to avoid death of bone cells.