Investigation on profile of microchannel generated by electrochemical micromachining

Electrochemical micro-micromachining (EMM) is the key micromachining technology for the manufacturing of ultra size components and micro-profiles. Various types of profiles generated by the scanning method and the sinking and milling method with the help of straight, conical and reversed taper micro tool were investigated. Simulation models of different shaped tools are presented and the current density distribution along the side wall and top and bottom surface of workpiece during blind microchannel generation are calculated to predict the shape of cross sectional profile. It was predicted that generation of microchannel with least taper angle of sectional profile was possible with reversed taper micro tool. It was also predicted that generation of microchannel with lesser taper angle of sectional profile was possible with conical micro tool and later on, verified by practical experiments. The major process parameters investigated were electrolyte concentration, front end shape of micro tool and vibration of micro tool on surface finish. Taper angle of microchannel generated by the sinking and milling method is always lesser than that of microchannel generated by the scanning machining layer by layer method. Cross sectional profile generated by reversed taper micro tool will have the tendency to be least tapered or without taper depending on reversed taper angle of the micro tool. Taper angle of blind microchannel generated by the 2° reversed taper micro tool was 17° which is considerably lower than 25° observed in the case of profile generated by straight micro tool. During the generation of blind microchannel by conical micro tool, taper angle of cross sectional profile decreases with the decrease in taper angle of micro tool generating the profile i.e. 14.5° taper angle of profile generated by conical micro tool having 10.5° taper angle and 5.14° taper angle of profile generated by conical micro tool having 4.34° taper angle.