The study of different flow fields at the corner during the electrochemical machining of internal gear

In this paper, a new method of electrochemical machining with sheet metal electrode (SME-ECM) is innovatively proposed to meet the challenges of internal gear machining. During the electrochemical machining of internal gears, the distribution of electrolyte flow around the corner area of the internal gear is a critical problem, because the dimensional accuracy at the corner directly determines the sidewall accuracy of the internal gear. In view of the phenomena such as stray flow field, gas accumulation in the machining corner area, and uneven removal in different machining areas during the machining process of internal gears, this paper carries out theoretical analysis and experimental investigation on the three flow field models of forward flow (Ff), reverse flow (Rf), and lateral flow (Lf) through multi-physics coupling simulation, flow field observation, and machining experiment. The processing characteristics of the corner area under the influence of different factors (flow field model, processing stage, flow rate, gas distribution) are obtained. The results show that under the same electrolyte pressure, the Lf model has the least residual gas in the corner region, with a gas content of less than 1.5e-5, and the machining current could reach 2.92 A, which has a significant advantage in the processing uniformity, indicating that the Lf flow field model has the advantage of electrochemical machining of internal gears. The research in this paper lays a theoretical foundation for further electrochemical machining of internal gears.