Efficient fabrication of zero taper µ-electrode using novel dry µ-electrical discharge turning

Abstract

Micromachining is essential for producing components smaller than 1000 µm and is increasingly significant due to the trend toward miniaturizing industrial products. Tool-based micromachining techniques like µ-turning, µ-grinding, µ-EDM, and µ-ECM offer benefits in productivity, efficiency, adaptability, and cost-effectiveness. Modern industrial products require high dimensional accuracy and superior surface finishes. µ-EDM is particularly promising for economically producing complex microfeatures with high precision. However, the high tool wear rate in µ-EDM requires on-machine microelectrode fabrication, which is essential for creating micro-sized holes and channels during µ-EDM operations. A major challenge lies in achieving high dimensional accuracy and minimal taper in microelectrodes. Additionally, there are health concerns related to hydrocarbons produced from liquid dielectrics. This research explores fabrication of microelectrodes using dry µ-ED Turning. Five machining strategies were employed, using stationary block electrical discharge turning (SB-EDT), moving block electrical discharge turning (MB-EDT), and their combinations to produce microelectrodes with improved surface finishes and minimal taper. Gaseous dielectrics significantly reduce harmful emissions and contamination, creating a safer working environment while minimizing environmental pollution. The taper issue was significantly mitigated in microelectrodes fabricated using MB-EDTd, achieving nearly zero taper with a surface finish of 2.04 µm. MB-EDTd also achieved highest material removal rate, producing a microelectrode with an average diameter of 428 µm. Scanning electron microscope (SEM) micrographs and surface finish analyses were conducted to examine the effects of various parameters, such as discharge currents and linear feed speed. The findings highlight the potential of µ-EDM with gaseous dielectrics to enhance microelectrode fabrication process.