Investigations into side gap in wire electrochemical micromachining (wire-ECMM)

Electrochemical machining (ECM) process is now in application in various industries like maritime, automobile, and aerospace. Wire-ECM, a variant of ECM, is now under investigation, for its applications in electronics industries for the fabrication of PCB on conductive metals like copper and in medical industries for the fabrication of micro needles with textures on its surface for the painless delivery of drugs. One of the most important parameters in wire-ECM is side gap. This paper aims at obtaining minimum side gap for the given machining conditions. In order to achieve this, three different workpieces of Al, Cu, and stainless steel are examined. Effects of different electrolytes on the side gap are also examined. Later on, different electrolytes at different temperatures are used to study their effect on the side gap. Finally, optimum parameters are determined in order to keep the side gap to a minimum level. In order to keep the findings significant for industrial applications, machining rate is kept as high as 5 μm/s. Other relevant process parameters are so derived that the machining process can attain stability at high feed rate. To realize this, regulated DC power supply is used. Average side gap was finally reduced to 26.8 μm using a commercially available copper wire of diameter 90 μm.