Effect of discharge parameters on the pit crater morphology in electrical arc machining of 6061 aluminum alloy

Abstract

Electrical arc machining has become an important method to meet the high-efficiency processing needs of difficult-to-cut materials, and its machining characteristics have attracted considerable attention. This study focuses on the characteristics of single-pulse arc machining and aims to investigate the effect of different discharge parameters on the morphology of the craters formed in 6061 aluminum alloy material. The goal is to provide theoretical support for optimizing the machining process and improving surface quality. A single-pulse arc machining experimental platform was built, and experiments were conducted with varying workpiece polarity, discharge current, and discharge duration parameters. Craters on aluminum alloy were obtained under different working conditions. The morphology of the craters was examined using scanning electron microscopy (SEM) and optical profilometry, and the discharge channels during single-pulse arc machining were observed using a high-speed camera. The influence of machining parameters on discharge crater morphology was analyzed. The results showed that under the same machining parameters, craters formed under positive polarity exhibited deeper depths, larger volumes of material removal, and smaller discharge crater diameters. Under positive polarity, with a discharge current of 400 A and a duration of 4 ms, the maximum material removal volume of the discharge crater was 1.1990 mm³. High-speed observations revealed that under positive polarity machining and high discharge currents, the arc discharge channel quickly formed and expanded, aiding in the removal and ejection of molten metal from the workpiece surface under the influence of high-temperature gases, thus promoting an increase in discharge crater volume. This study provides important theoretical guidance for further optimizing the machining process.