Investigation on performance characteristics of micro-EDM dressing for the fabrication of micro-rod(s) on Ti-6Al-7Nb biomedical material

The performance characteristics of micro-EDM dressing were investigated based on some real-time and offline responses for the fabrication of micro-rod(s) on a novel Ti-6Al-7Nb biomedical material. These characteristics evaluated along the micro-rod length at three different discharge energy settings were analyzed by monitoring the discharge gap condition captured through an in house developed pulse-discriminating system (PD). The experimental results show that the normal pulse was more (∼90%) in the low energy setting (E1). In contrast, arcing was more (∼28%) in the high energy setting (E3). Pulse frequency was found more (∼60 Nc/s) in E1. However, due to an increase in the 'idle' time, it significantly decreased (∼25 Nc/s) along the machining length. Material removal rate, however, was found more (∼5.7 × 103, µm3/s) in E3. The specific energy was found very high (∼9 MJ/mm3) in E1 since the process spent additional energy to remove the re-solidified molten metal. The tool wear ratio was, on the other hand, found very high (∼2.1) in E1 due to prolonged exposure to discharges and experiencing higher total discharge energy by the work-tool interface. E3 was found more suitable for fabricating dimensionally accurate micro-rod(s) on this material because of less tool wear.