Surface Finish Optimization of Magnesium Pieces Obtained by Dry Turning Based on Taguchi Techniques and Statistical Tests

Magnesium is one of the lightest metallic materials and is used in industries such as aeronautics or aerospace because of its excellent weight to resistance ratio. The surface finish is a key quality characteristic in dry turning of magnesium pieces and is often affected by multiple factors within the machining process. Factors such as feed rate, cutting speed, tool coatings, and the interactions among these were investigated in this experimental study. The objectives of this work were to identify the main factors that influence the dry turning of magnesium and to select the optimal manufacturing conditions that result in minimum surface roughness. To achieve these objectives, the smaller-the-better characteristic from the Taguchi method was applied to the average roughness R(a). Using an orthogonal experimental design approach, the signal-to-noise (S/N) ratio was used to quantify the amount of variation present in the surface roughness. Then, graphical exploratory data analysis was conducted, and the variability in the S/N ratio of surface roughness was modeled via analysis of variance (ANOVA) fixed-effect analysis and Snedecor's F-tests. This statistical modeling, together with Least Significant Difference testing permitted different combinations of cutting conditions to be classified into two groups: (I) optimal combinations and (II) the remaining combinations.