Experimental Analysis and Process Monitoring of Cutting Force, Vibration, Surface Roughness, and Cylindricity in Turning of C45 Steel

This study examines the effects of cutting speed, feed rate, and depth of cut on cutting force, vibration, surface roughness, and geometric accuracy during dry turning of C45 steel (EN 1.0503) using a Taguchi L9 orthogonal design. Cutting force, RMS acceleration, surface roughness (Ra and Rz), and form deviations (straightness, roundness, and cylindricity) were measured for nine machining conditions. Vibration decreased with increasing cutting speed and increased with increasing depth of cut, whereas cutting force showed no consistent dependence on cutting speed and increased at the largest depth of cut. Ra and Rz were generally lower at higher cutting speeds. The maximum active cutting force was 730.60 N in Experiment 7, while the maximum RMS vibration was 19.09 m/s2 in Experiment 3. Exploratory Pearson analysis across the nine conditions indicated r = 0.678 between vibration and Ra, r = −0.769 between vibration and cylindricity deviation, and r = 0.329 between cutting force and vibration. Because no independent machining repetitions were performed, these relationships are descriptive and do not establish causality, statistical factor significance, or a validated predictive model. The study therefore presents the integrated force–vibration–surface–geometry measurements as a process-screening framework and identifies methodological requirements for subsequent replicated and frequency-resolved experiments. The vibration indicator is the RMS acceleration derived from the tangential and radial components; the sensor specification provides a programmable low-pass-filter range up to 260 Hz, although the actual internal filter setting used during acquisition was not documented.