Stray current affected zone in electrochemical jet machining

The stray current affected zone (SCAZ) in electrochemical jet machining (EJM) poses a significant and often unavoidable challenge. This study offers an in-depth analysis of the morphological characteristics and formation mechanisms of SCAZ in EJM through a combination of machining experiments and surface characterization. By investigating various workpiece materials and electrolytes, we identify that stray corrosion phenomena are highly dependent on the specific material-electrolyte combinations used. Although applying ultra-short pulses of 750 ns enhances shape accuracy, it does not fully prevent pitting corrosion. Conversely, the bipolar pulse technique effectively reduces pitting, though stray oxidation remains an issue. As a result, post-finishing processes are crucial. Notably, plasma electrolytic polishing is demonstrated to be highly effective in removing stray oxidation, achieving a glossy surface on SUS304 in just 3 s while maintaining dimensional accuracy.