Optimization of Measurement Area Selection for Accurate 3D Surface Topography Characterization in High-Feed Tangential Turning of 42CrMo4 Alloy Steel

Accurate characterization of 3D surface topography is essential for assessing the quality of machined components. This study investigates the influence of measurement area selection on the evaluation of roughness parameters in high-feed tangential turning of 42CrMo4 alloy steel. Cylindrical surfaces were machined using different process parameters, and their surface topography was analyzed by varying the size of the areal measurement region. Key roughness parameters were examined to determine the impact on the reliability and consistency of surface characterization. The results highlight how different measurement areas influence roughness values and their variations. The findings contribute to improved metrological practices in tangential turning, and they are particularly relevant for precision machining applications where surface integrity plays a critical role. The area width of the measurement area was shown to play a critical role in data reliability. The results showed that Sa and Sk stabilized after 5.5–6.0 mm, while Ssk and Sku stabilized earlier, at approximately 5.0 mm. Spk and Svk required the longest evaluation area widths, up to 6.0 mm, to achieve consistent values.