Process Control in Jet Electrochemical Machining of Stainless Steel through Inline Metrology of Current Density

Abstract

Jet electrochemical machining (Jet-ECM) is a flexible method for machining complex microstructures in high-strength and hard-to-machine materials. Contrary to mechanical machining, in Jet-ECM there is no mechanical contact between tool and workpiece. This enables Jet-ECM, like other electrochemical machining processes, to realize surface layers free of mechanical residual stresses, cracks, and thermal distortions. Besides, it causes no burrs and offers long tool life. This paper presents selected features of Jet-ECM, with special focus on the analysis of the current density during the machining of single grooves in stainless steel EN 1.4301. Especially, the development of the current density resulting from machining grooves intersecting previous machining steps was monitored in order to derive systematic influences. The resulting removal geometry is analyzed by measuring the depth and the roughness of the machined grooves. The correlation between the measured product features and the monitored current density is investigated. This correlation shows that grooves with the desired depth and surface roughness can be machined by controlling current density through the adjustment of process parameters. On the other hand, current density is sensitive to the changes of working gap. As a consequence of the changes of workpiece form and size for the grooves intersecting premachined grooves as well as the grooves with a lateral gap, working gap, and current density change. By analyzing monitoring data and removal geometry results, the suitability of current density inline monitoring to enable process control is shown, especially with regards to manufacture products that should comply with tight predefined specifications.

Product/Process Fingerprint in Micro Manufacturing

“…As far as machining processes are concerned, Process Fingerprints were established and validated for electrical discharge machining (EDM) byŚwiercz et al [9], for micro EDM drilling by Bellotti et al [10], for plasma electrolytic polishing by Danilov et al [11], for jet electrochemical machining by Yahyavi Zanjani et al [12], for nanosecond pulsed laser ablation by Cai et al [13], and for micro grinding by Fook et al [14]. c.…”

Design of a user-friendly human machine interface for jet electrochemical machining

“…The current density, which amounts up to 1000 A/cm², is localised due to the shape of the closed free jet [5]. Therefore, a high localisation and a high precision of the removal geometry can be achieved.…”

Real-time monitoring of process current and its correlation with micro-feature accuracy and surface topography in electrochemical micromachining of nitinol

“…Real-time monitoring plays a pivotal role in ensuring the precision and efficiency of electrochemical micromachining (ECMM), a cutting-edge technique used for high-precision fabrication in various industries like biomedical, electronics, military, and aerospace [1]. ECMM involves the controlled disintegration of work material through electrochemical dissolution [2].…”