Theoretical and experimental investigations of surface roughness, surface topography, and chip shape in ultrasonic vibration-assisted turning of Inconel 718

When processing difficult-to-cut materials, conventional turning (CT) typically suffers from the problems of large cutting force, difficult chip removal, and serious tool wear, resulting in deteriorated processing quality, reduced processing efficiency, and increased processing costs. In addition, special-purpose machine tools used for ultrasonic machining exhibit disadvantages, such as narrow application scope, high manufacturing cost, and poor universality; thus, they are not conducive to being popular in actual production and processing. Accordingly, this study analyzed the characteristics of ultrasonic wave, the mechanism of ultrasonic vibration-assisted turning (UAT), and the formation of a machined surface in UAT. Moreover, the machining system of UAT was established. This system applied an ultrasonic wave vibration device to an engine lathe to meet the requirements of vibration cutting in actual production. Simultaneously, Inconel 718, a typical and widely used difficult-to-cut material, was selected for the experimental study. The machining effect of UAT was analyzed in detail, including surface roughness, surface topography, and chip shape. Results indicated that ultrasonic amplitude, cutting speed, depth of cut, and feed rate exert considerable influences on the machining effect. UAT can achieve this effect, which is difficult to realize via CT, under the condition of a reasonable selection of technological parameters. This research can provide theoretical support and experimental basis for the development and practical application of UAT.