A novel ultrasonic-assisted ball burnishing device to apply high-frequency vibrations in feed direction: Design and performance evaluation

Abstract

To improve the wear resistance of Al7075-T6 parts, surface processing techniques like burnishing are used, with ultrasonic vibrations being utilized in recent years to further enhance surface properties. However, many researchers focus on using ultrasonic vibrations on radial direction, and less research has been conducted on the combination of ultrasonic vibrations in the tool feed direction with the burnishing process. Therefore, this research sought to study the design and construction of ultrasonic vibration-assisted burnishing equipment in feed direction, and then, subject the samples to ultrasonic-assisted burnishing with different vibration amplitudes. Further, various part surface parameters such as surface roughness, microhardness, grain size, friction coefficient, and wear rate were evaluated in a dry wear test. It was found that although ultrasonic vibration-assisted burnishing in the feed direction did not have a significant impact on $R_a$ , it reduced other parameters like $R_{sk}$ and $R_{ku}$ . Additionally, it is demonstrated that increasing the amplitude of vibrations led to the improvement of overall surface roughness quality. In terms of surface hardness, it was found that utilizing a range of 30 μm for amplitude yielded the most optimal results, increasing the surface hardness by an impressive 17.8% in comparison to the turned sample. Wear tests revealed that the average friction coefficient decreased by 29% and 3.1% with ultrasonic burnishing and burnishing, respectively, compared to the turned sample. Furthermore, the lowest wear rate was belonged to ultrasonic-burnished sample with an amplitude of 30 μm.