OPTIMIZATION OF THE EFFECT OF PROCESSING PARAMETERS ON SURFACE ROUGHNESS AND MATERIAL REMOVAL RATE IN CNC MILLING OF AL-7075 MATERIAL

Abstract

This paper presents the results of the influence and optimization of some machining parameters on the surface roughness (Ra) and material removal rate (MRR) in the milling process of AL-7075 on the CNC machine. The signal ratio (S/N) in the Taguchi method and the analysis of variance (ANOVA) were selected to determine which machining parameters significantly and percentage contribution to Ra and MRR. Then, the response surface method (RSM) was used to optimize the multi-objective Ra and MRR criteria. The results show that machining parameters directly influence Ra and MRR. Specifically, Ra is significantly affected by spindle speed, feed rate, coolant, and depth of cut with percentages of 37.12%, respectively; 12.56%, 12.07%, and 10.13%, while MRR is mainly affected by feed rate, depth of cut with percentages of 41.68% and 47.29%. Finally, the results of multi-factor optimization analysis by RSM indicate that with the coolant condition (on), the feed rate 450 mm/min, depth of cut 0.369 mm, and spindle speed 5500 r/min obtain the optimum value of Ra and MRR are 0.159 µm and 32.019 g/min, respectively.