An experimental study on dry drilling performance of Al6082 alloy for enhanced productivity, hole quality and surface morphology
Abstract
Drilling is an important machining process for producing accurate holes in engineering components, where hole quality and dimensional accuracy directly influence assembly and functional performance. Therefore, understanding the effects of drilling parameters on machining performance, surface integrity, and hole geometry is essential. In this study, the dry drilling characteristics of Al 6082 alloy were investigated using spindle speed, feed rate, and high-speed steel drill bit diameter (6, 8, and 10 mm). Average values of cutting time, maximum temperature, surface roughness were considered as responses, while hole quality was evaluated in terms of circularity, cylindricity, and perpendicularity errors. Taguchi’s orthogonal array and response surface methodology (RSM) were employed for experimental design, modeling, and analysis. The results showed that spindle speed was the dominant parameter affecting cutting time. Spindle speed- 660 rpm feed rate- 0.25 mm rev−1 feed rate, drill diameter- 6 mm yielded a minimum RSM-predicted cutting time of 2 s. Drill diameter significantly influenced both maximum temperature and surface roughness. A minimum surface roughness of 1.20 µm was obtained at 660 rpm, 0.10 mm rev−1, and 6 mm drill diameter, whereas the minimum RSM-predicted average maximum temperature of 29.6 °C was obtained at 660 rpm, 0.16 mm rev−1, and 10 mm drill diameter. The developed models exhibited R2 values of 97.65%, 93.03%, and 97.49% for cutting time, temperature, and surface roughness, respectively, indicating good predictive capability. Hole quality analysis showed that feed rate −0.10 mm rev−1 and spindle speed- 660 rpm reduces perpendicularity error. Other hand, feed rate- 0.10 mm rev−1, spindle speed- 75 rpm reduces circularity, and perpendicularity errors. The average measurement errors for circularity, cylindricity, and perpendicularity were 0.657%, 0.958%, and 7.741%, respectively. FESEM analysis revealed more uniform feed marks and minimal adhesion at 75 rpm, whereas 660 rpm promoted plastic deformation, smeared layers, and chip redeposition, indicating increased frictional heating and adhesion.