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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°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.

Friction drilling processes are used commonly in hot forming operations. This process is similar to drilling processes but without using chip. This process is used especially for joining thin-walled metal components. In this study, the drilling process using centerdrill is investigated both experimentally and numerically. The finite element analyses (FEA) were conducted using deform-3D software based on finite element method (FEM). In this study, an analytic model is developed, which calculate the process parameters as torque and axial power, heat transfer coefficient. A comparison was also made for temperature, torque and axial force obtained from experimental and numerical analyses. At the end of the study, while the torque and axial force values decrease with increasing of spindle speed, temperature values of centerdrill and workpiece increase with increasing of spindle speed. A good consistency between both experimental and FEA simulations was found during the centerdrill process.

In this study, biomechanical behaviors of three different screw materials (stainless steel, titanium and cobalt-chromium) have analyzed to fix with triangle fixation under axial loading in femoral neck fracture and which material is best has been investigated. Point cloud obtained after scanning the human femoral model with the three dimensional (3D) scanner and this point cloud has been converted to 3D femoral model by Geomagic Studio software. Femoral neck fracture was modeled by SolidWorks software for only triangle configuration and computer-aided numerical analyses of three different materials have been carried out by AnsysWorkbench finite element analysis (FEA) software. The loading, boundary conditions and material properties have prepared for FEA and Von-Misses stress values on upper and lower proximity of the femur and screws have been calculated. At the end of numerical analyses, the best advantageous screw material has calculated as titanium because it creates minimum stress at the upper and lower proximity of the fracture line.