Experimental Analysis and Optimization of Thrust Force in the Orthopedic Drilling Process Using the Tool Coated with Titanium Nitride Nano Coating by the Physical Vapor Deposition Method

One of the most significant and applicable machining processes in surgeries and medical engineering is the bone drilling process. In this process, it is intended to minimize the axial force on the bone tissue during surgery. To reduce force, different methods have been considered; including the use of a variety of lubricants, ultrasonic oscillations, material replacement, tool geometry, and also the use of coated tools. The purpose of this paper is to investigate the effect of a specific type of nano coating on steel tool, and to investigate the effect of effective input parameters on force behavior in orthopedic drilling with medical requirements in mind. In this study, the polymeric material of poly-methyl-meta-carylate (PMMA), which has similar properties to the bone, was selected; and by creating titanium nitride nano coating on the tool, the effect of tool rotational speed, feed rate, and the tool diameter on the drilling process force have been extracted using the design of experiment by the response surface method, modeling and second-order linear regression equation governing the model. The optimum values of each input parameter are also presented in order to achieve the minimum and the best amount of force created during orthopedic drilling. The results show that the creation of titanium nitride nano coating reduces the force by 40 percent. Also, the axial force with the maximum cutting speed, the minimum feed rate, and in the tools with smaller diameters has been significantly reduced.