Effect of ultrasonic elliptical vibration turning on the microscopic morphology of aluminum alloy surface

Abstract

The present research envisages the effect of ultrasonic elliptical vibration turning (UEVT) on the surface morphology of aluminum alloy, using a single-excitation ultrasonic elliptical vibration system. By constructing the kinematic trajectory model of the ultrasonic tool, the effects of cutting parameters and ultrasonic amplitude on the surface morphology of aluminum alloy were studied. The experimental results show that the ultrasonic amplitude and feed rate exhibited a significant effect on the surface morphology of the aluminum alloy. Under the action of high-frequency vibration, the tool’s flank had the effect of ironing and dressing the machined surface. In the cutting process, the tool-chip separation and high-frequency intermittent cutting were realized, and the surface quality was improved. The best ultrasonic parameter measured by experiment was at the amplitude A = 3 μm. At this time, the overlapping faces of the two elliptical trajectories increased in the feed direction, the vibration height (Rth) in the feed direction decreased, and the difference in the height of the surface decreased. When the feed rate (fv) was low, the material removal per unit time was less, the cutting force and cutting heat were relatively small, and the “scaly texture” was more detailed and denser. Experiments show that the surface height arithmetic mean (Sa) and the line roughness (Ra) of UEVT were better than the conventional turning (CT) under the same parameters. The single-excitation ultrasonic elliptical vibration system designed in this experiment employed the structure of the turning tool itself to realize the ultrasonic elliptical vibration, which saved the cost and workspace. This experiment provides an important aspect in the study of surface quality of aluminum alloy processing, while ensuring the cutting efficiency at an appropriate ultrasonic amplitude (A = 3 μm) and low feed rate, in order to obtain the best surface morphology.