Optimization of processing parameters of a developed new driller system for orthopedic surgery applications using Taguchi method

In bone drilling process during the surgical operations, heating increases due to high bone/drill contact friction that damages the bones and soft tissues. The overheating is usually recognized as the temperature rise exceeds 47 A degrees C, a critical limit, above which the drilling causes osteonecrosis. In this study, a new driller system is developed to prevent the overheating in orthopedic surgeries. It has a closed-circuit cooling system to reduce the undesired temperature rise during the drilling process. It is also designed and manufactured as a prototype and tested experimentally in vitro by drilling fresh bovine bones using different processing parameters. In the drilling tests, the temperature levels of the bones are measured using thermocouple sensors. Based on the measured results, the driller system provides a valuable temperature reduction around 25 % to prevent necrosis in low spindle speeds (rpm) usually preferred by surgeons. The measured temperatures from the tests of the driller system with a cooling system were compared with the use of regular bone drilling process without cooling. The optimum processing parameters of the new driller system with/without coolant are calculated using the Taguchi method, and the most effective parameter is found as rpm.