MONITORING OF SURFACE TOPOGRAPHY IN CNC TURNING OF Co–Cr–Mo BIOMATERIAL BY USING ACOUSTIC EMISSION SIGNALS

Manufacturing industries are always in search of preparing quality implants from Co–Cr–Mo biomaterial by doing improvements in their processes. CNC turning is basically adopted for preparing a practical surface of femoral head of hip implants. The online monitoring systems such as acoustic emissions (AEs) from the machining zone provide knowledge of the deformation characteristics of the work material in machining, which affect the machined surface topography and integrity. In this study, CNC turning experiments by using CBN insert were planned according to RSM CCD in dry cutting environment. Surface generation was monitored with the help of AE setup by correlating AE RMS voltage and counts to the surface integrity of machined surfaces. Cutting speed, feed rate and depth of cut show significant effects on the AE RMS voltage. The feed rate and depth of cut, however, also show dominating effects on the AE counts. It is also observed that at lower force components, the amplitude of AE RMS voltage corresponds to a lower surface roughness (Ra=0.97 μm) and the counts pattern of AE signal shows nonuniform behavior which corresponds to a higher surface roughness (Ra=1.06 μm); however, the smooth surface produced with a lower Ra value (0.89 μm) shows uniform counts pattern of AE signals.