Micro Tool Electrode Fabrication Using Edge Electrode Discharge Grinding

This paper describes an edge electrode discharge grinding (EEDG) approach, in which the edge of a stainless steel slice is used as the tool electrode for fabricating micro tool electrodes and parts. EEDG is an appropriate method for producing micro electrodes due to its good surface quality, a low running cost and quick set-up. It is also capable of machining very fine detailed profile due to its sharp edge. The flexibility of EEDG process was investigated using different tool paths and different methods of tool electrode wear compensation to machine micro electrodes in a variety of shapes. A series of experiments were carried out to find the effects of discharge gap and discharge energy on the material removal rate (MRR) and the tool electrode wear (TEW). An optimum range of discharge gap is found to be from 12 to 15 mu m for both high material removal rate and low tool electrode wear. MRR is high at high open circuit voltages and in a general upward trend along with the increase of the nominal capacitance. TEW rises with the increases of nominal capacitance and is high at high open circuit voltages. In addition, the surface quality of the machined surfaces obtained by EEDG in rough and finish machining was compared. Base on the experiments, a cylindrical microelectrode and an hourglass-shaped microelectrode were fabricated by EEDG through two processes of rough and finish machining.