The tool electrode wear and gap fluid field simulation analysis in micro-EDM drilling of micro-hole array

With the micro-hole array structure has been widely used in industrial areas, such as inkjet printer nozzle, oil nozzle, spinneret and so on, its processing accuracy significantly affects the performance of the product. In the machining of micro-hole array by micro-EDM drilling, unavoidable tool electrode wear and frequent occurrence of abnormal discharges such as short circuit and secondary discharge caused by the difficulty in removing discharge debris are the main factors affecting machining geometric and dimensional accuracy. In this study, the flow velocity simulation analysis of working fluid playing a crucial role in the flushing of discharge debris and the experimental study on the axial wear of tool electrode are explored in order to ensure the machining accuracy of micro-hole array. By changing the parameters of tool electrode diameter and machining depth in the fluid field simulation analysis, the gap velocity distribution under different depth-diameter ratios is obtained. Simulation results show that the gap flow velocity decreases with depth-diameter ratios increasing. For different depth-diameter ratios in the micro-hole array processing, the tip morphology evolution and the wear of tool electrode are considered, which show that the electrode tip morphology tends to be stable and the axial wear of the tool electrode could be compensated evenly. In addition, the characteristics of tool electrode axial wear are explained based on the simulation results of gap flow field, which verifies the effectiveness of the flow field simulation and provides a reference for formulating electrode wear compensation strategy and improving machining accuracy to some extent.