Optimization of surface roughness in finish milling of AISI P20+S plastic-mold steel

In this study, the performance of the cutting parameters used in the finish milling of the AISI P20+S plastic-mold steel were researched and the optimum machining conditions were identified.Experiments were made according to the Taguchi L8 (4 1 × 2 3 ) orthogonal array.The evaluation of the experimental results was based on the signal/noise (S/N) ratio.Control factors for the optimum surface-roughness values were determined using the Taguchi method.Four different cutting speeds (100, 150, 200, 250) m/min, two different feed rates (0.1, 0.2) mm/r, depths of cut (0.12, 0.16) mm and cooling methods (dry and wet) were selected as the control factors.The effects of the control factors on the surface roughness were determined with an analysis of variance (ANOVA) using the experimental results.A multiple regression analysis was also conducted using the experimental results.A higher correlation coefficient (R 2 ) was obtained with a linear regression model, which showed a value of 0.923 for Ra.Finally, confirmation tests were performed and they showed that the optimization was successfully implemented.Using the Taguchi analysis, we found the optimum results for the surface roughness at a cutting speed of 150 m/min, a feed rate of 0.1 mm/r, a depth of cut of 0.16 mm and the wet cooling method.The results of the calculation and confirmation tests for the Ra were 0.288 μm and 0.296 μm.