Fabrication of micro rod electrode by electrical discharge grinding using two block electrodes

With the development of micro-electro-mechanical system (MEMS), micromachining techniques have become a hot issue in modern industry. As the tools of micromachining, the requirement of micro rod electrodes has also greatly increasing. Wire electrode discharge grinding (WEDG) and Block electrode discharge grinding (BEDG) are effective approaches to produce micro rod electrodes. However, in order to get micro rod electrode with desired diameter, both methods need the help of an on-machine measuring device in the processing of machining, which increases the complexity of the equipment. In this study, electrical discharge machining grinding using two block electrodes (EDG-TBE) was created in an effort to overcome the problem of measurement and reduce the complexity of the equipment. In this method, rod electrode with initial diameter was driven through a narrow slit between two block electrodes. The desired diameter is determined by the width of narrow slit and the discharge gap. Because the discharge gap is determined by power supply parameters, desired diameter can be obtained as long as the width of slit is set correctly when power supply parameters is fixed. In the experiment, the machining efficiency and accuracy of micro rod electrode were investigated. Experimental results show that machining efficiency of micro rod electrode is higher in EDG-TBE than that in BEDG. In addition, the error between machined diameter and target diameter is less than 2 μm and the cylindrical error of micro electrode is also less than 2 μm in EDG-TBE.