Insights into process innovation through ultrasonically agitated concentric flow dielectric streams for dry wire electric discharge machining

Abstract

ABSTRACT Application of gaseous dielectric in place of liquid dielectric for wire electric discharge machining (WEDM), popularly known as dry wire electric discharge machining (DWEDM), offers technological solutions to some environmental and metallurgical issues pertaining to process. However, conventional side jet stream of dielectric in dry WEDM renders ineffective debris removal from sparking gap to cause unwanted arcing. Moreover, side thrust on the wire surface tends to induce wire vibrations and results into uneven geometrical profiles. To harness full potential of DWEDM technology, it is imperative to improve cutting characteristics of process by minimizing the adverse impacts of side jet stream of dielectric. In this research work, the authors have conceptualized and demonstrated the idea of using concentric flow pattern of gaseous dielectric as a novel technological solution to limitations of DWEDM process by introducing ultrasonic-agitated concentric dry wire electric discharge machining (UCDWEDM). Experiments have been performed on Ti–6Al–4V material. Ultrasonically agitated pressurized air streams were supplied through indigenously developed concentric and side flow nozzles mounted on experimental set up. The experimental results showed that concentric flow mode of dielectric supply has outperformed the conventional side flow mode with 42% higher CV, 22% lower SR, and 8% lesser KW. Process mechanism of UCDWEDM is based on high velocity of air in concentric flow and ultrasonic-agitation in spark gap and suggested that UCDWEDM has potential to replace conventional dielectric supply system in DWEDM.