Machining of micro features through µ-ECSM process and evaluation of surface integrity

Abstract

In the present experiment, micro features were fabricated on titanium alloy by means of the micro-electrochemical spark machining (µ-ECSM) process and the micro-electro discharge machining (µ-EDM) process, using similar electrical parameters. However, in case of the µ-ECSM, the types of electrolyte (KOH, NaOH, KOH+NaOH) and their concentration (0.5 M to 2.5 M) varied from that of the µ-EDM process. In course of the study, different machining output parameters, such as, material removal rate (MRR), recast layer (RCL) thickness, heat affected zone (HAZ) and surface topography, were analysed and compared. The results indicated that the µ-ECSM process produces higher MRR (7.29 times), RCL thickness (0.436 times) and HAZ (0.595 times) as compared to the µ-EDM process. Moreover, the mixed (KOH+NaOH) electrolyte at 0.5 M concentration, 25 V machining voltage, 15% duty factor and 10 kHz of frequency showed better machining performance as compared to the parent electrolyte and produced lower RCL thickness (3.54 µm) and HAZ (26.83 µm), respectively. The surface topography of the work piece, machined by the µ-EDM process, showed rough surface whereas the NaOH electrolyte-based µ-ECSM process produced smoother and clean surface.