Influence of flank micro-texturing on mechanical and thermal responses during cortical bone end milling

Excessive cutting forces and thermal generation during bone machining can compromise tissue integrity and increase the risk of thermal osteonecrosis. This study investigates the effects of flank-surface micro-texturing of end-mill cutters on cutting force and temperature during cortical bone milling. Carbide end-mills with untextured, dimpled, linear-grooved, and zigzag-grooved flank surfaces were examined, followed by an analysis of three different groove orientation relative to the cutting edge (0°, 45°, and 90°). Milling experiments were performed on bovine cortical bone using a three-axis CNC machine under controlled cutting conditions. Resultant cutting forces were assessed with a dynamometer, and surface temperatures were recorded through infrared thermal imaging. All these micro-textured tools delivered lower forces and temperatures than the reference untextured ones. Linear flank grooves yielded the greatest reductions in both peak and average responses compared to other textures. Perpendicular groove orientations suppressed steady-state forces and thermal accumulation compared to parallel and oblique grooves. These findings demonstrate that, under the investigated laboratory conditions, flank-surface micro-texturing can reduce measured mechanical and thermal responses during cortical bone end-milling. The reduction in temperature is potentially beneficial from a thermal-safety perspective; however, the present experiments do not establish a direct reduction in thermal osteonecrosis risk under clinical conditions.