Advanced micromachining of SS304 using electrochemical jet machining: Experimental analysis, depth characterization, and process optimization

A non-conventional micromachining process for creating precise features on difficult-to-machine materials without causing any mechanical and thermal damage to the material is electrochemical jet machining (ECJM). In this research work, the effect of stand-off distance (SOD) and voltage on machining depth and opening formation during the ECJM of SS304 stainless steel material is studied. A 2 M NaCl electrolyte, a nozzle inner diameter of 300 μm, and voltages of 40 V, 50 V, and 60 V with three SODs of 300 μm, 500 μm, and 700 μm were used in the experiment. The optical microscopy was used to measure the machining depth and opening size, and three experimental trials were conducted for each set of parameters to check the repeatability of the results. The result of the experiment revealed that voltage and SOD have a significant effect on machining depth. The depth increased from approximately 380-410 μm at 40 V to 690-710 μm at 60 V at a fixed SOD of 700 μm. The material removal rate was significantly enhanced by reducing the SOD; at 300 μm SOD, the machining depth increased from 685 to 710 μm at 40 V to 840-890 μm at 60 V. The opening size also increased from around 0.536 mm at 40 V and 700 μm SOD to 0.843 mm at 60 V and 300 μm SOD. A comparative study showed that lowering the SOD from 700 μm to 300 μm increased the machining depth by more than 70% for a given voltage. This was because the electric field and current density were higher. The experimental results were found to be reliable and consistent, as there were no variations in the trends. This research measures the influence of SOD and voltage on the depth of drilling with a constant flow rate of electrolyte. The experimental result showed that to achieve machining depth, dimensional accuracy, and efficiency in ECJM of SS304, the optimal selection of voltage and stand-off distance is required.