Machining of micro holes in titanium Alloy by electro discharge machining

Abstract

The growing scenario towards the miniaturization of products with more functionality and light weight has lead to the development of precision machining technologies in the area of micro-machining. Applications of micro-features on super light and high hardness alloys have made Electric Discharge Machining (EDM) as an important, reliable and cost-effective machining process. Due to its negligible machining forces and high repeatability of the process, EDM has become one of the best processes for achieving dimensionally perfect micro-features in hard-to-machine materials like Ti-6Al-4V. Though EDM is capable of machining any electrically conductive materials regardless of their hardness, challenges related to debris accumulation in the Inter Electrode Gap (IEG) and generation of secondary sparks during the EDM process are still unresolved. These machining issues affect the performance characteristics like machining rate, tool wear and surface finish. Hence this study aims to develop some assistive methods to integrate with existing EDM process to reduce the machining issues and improve the performance characteristics while machining micro-holes in Ti-6Al-4V alloys. newlineThe selection of pulse type and its corresponding control circuit is a key to successful machining of micro-holes using EDM. This study starts with experimenting and evaluating the types of pulse circuits and selecting a circuit based on performance measures. To effectively machine micro-holes of 500and#956;m on Ti-6Al-4V alloy, an experimental investigation was carried out using the Slope Control (SC) circuit following the Box Behnken design. Based on the literature survey and pilot experimental trails, the most influencing machining parameters on output responses such Material Removal Rate (MRR), Tool Wear Rate (TWR) and Surface Roughness (SR) were selected newline