Abstract

The surface quality of the machined parts is one of the most important product quality characteristics and one of the most frequent customer requirements. In this study the Taguchi robust parameter design for modeling and optimization of surface roughness in dry single-point turning of cold rolled alloy steel 42CrMo4/AISI 4140 using TiN-coated tungsten carbide inserts was presented. Three cutting parameters, the cutting speed (80, 110, 140 m/min), the feed rate (0.071, 0.196, 0.321 mm/rev), and the depth of cut (0.5, 1.25, 2 mm), were used in the experiment. Each of the other parameters was taken as constant. The average surface roughness () was chosen as a measure of surface quality. The experiment was designed and carried out on the basis of standard L₂₇ Taguchi orthogonal array. The data set from the experiment was employed for conducting the optimization procedures, according to the principles of the Taguchi method. The results of calculations were in good agreement with the experimental data. A certain discrepancy between the experimental results and calculations could be interpreted as the presence of measurement errors, many irregularities and deficiencies in the turning process, as well as environmental effects. The results presented in this work confirm the effectiveness of Taguchi’s technique in optimization of cutting processes.

Key words: turning process, surface roughness, Taguchi method, ANOVA, regression analysis.