Experimental Investigation of the Effects of Initial Surface Roughness on Ultrasonic Assisted Ball Burnishing of Al6061-T6

In the process of manufacturing, the operation of improving the quality of the surfaces is important due to the different working conditions, the resistance to corrosion and fatigue life, friction, the type of contact between the surfaces and appearance. The purpose of this research is the experimental investigation of burnishing process on the flat surface by ultrasonic vibration in order to investigate the initial surface roughness as an input variable as well as its interaction effect on the final surface roughness of aluminum Al6061-T6 alloy. Response surface methodology (RSM) was utilized to correlate the empirical relationship between input and output variables and their interaction effects. Experimental tests with a constant frequency of 20 kHz were done to find the effect of the initial maximum surface roughness, ultrasonic vibration amplitude and static load on the surface roughness. The results show that the initial surface roughness has no direct effect on the output surface roughness, but the effect of vibration amplitude and static load on the final surface roughness depends on the initial surface roughness. The higher static load is needed for the high surface roughness, and the increase of static load has decreased the effect of initial surface roughness on the surface roughness. Also, in high vibration amplitude by increasing the initial surface roughness, the surface roughness is increased and at low vibration amplitude by increasing the initial surface roughness, the surface roughness is decreased. By increasing the vibration amplitude and the static load, the surface roughness is increased. Furthermore, the amplitude of vibration, the interaction effect of static load and the initial maximum surface roughness and static load have the highest effect on the final surface roughness, respectively.