One of the most prevalent machining processes in medical treatments is bone drilling process. Bone drilling is very common in orthopedic surgeries, breakage treatments, bone sampling and dentistry. The advent of automatic surgery drills and CNC robots has initiated a breakthrough in bone drilling. During bone drilling, in case of excessive process force can cause breakage, crack initiation and severe damage to bone tissue. It is also possible that tool breaks in the bone. In this paper considering helix angle and point angle of the tool are considered as the most important geometrical parameters. Initially, using design of experiments and response surface method imposed force to the bone is modeled and the governing second order linear regression equation is derived and verified. Then using Sobol sensitivity analysis, with ability to quantify the sensitivity, it is attempted to investigate the effect of input parameters on drilling force. Finally, optimization of the process inputs is followed to find the best combination which yields the desired drilling force. The minimum drilling force state, within the range of input parameters, coincides with point angle of 90 and helix angle of 18. This minimal force is lower than the force in surgery tool and standard tool.
