Optimization of surface roughness and cylindricity using the Taguchi method in boring of S45C steel with tungsten steel and phosphor bronze damping materials

Taguchi optimization and regression analysis techniques were applied to evaluate the machinability of S45C medium carbon steel under dry boring conditions using tungsten steel and phosphor bronze as damping materials. The Taguchi experiments were configured in an L18 (2¹ × 3²) mixed orthogonal array, with the damping material, cutting speed, and feed rate selected as the control factors. The results showed that the surface roughness of the bored holes was determined mainly by the feed rate (contribution of 82.28%), while the cylindricity was dependent mainly on the damping material (contribution of 54.43%). The tungsten steel damper yielded a lower surface roughness and improved cylindricity for all values of the cutting speed and feed rate. Linear and quadratic regression models were constructed to predict the surface roughness and cylindricity as a function of the damping material, cutting speed, and feed rate. The prediction results obtained from the quadratic model showed particularly good agreement with the experimental measurements. The confirmation test results all fell within the calculated 95% confidence level. Thus, the Taguchi method effectively balanced the machining conditions in such a way as to minimize the surface roughness and cylindricity error.