Novel carbon nanotubes reinforced copper composite electrode for improved performance of electric discharge machining

Abstract Composite electrode fabrication is an effective strategy to improve the performance of the Electric Discharge Machining (EDM) process. In this work, a new copper/carbon nanotube (Cu/CNT) metal matrix composite electrode at a different volume fraction of CNT (0.35%, 0.70% and 1.05%) is developed using a spark plasma sintering (SPS) method. The real-time functional performance of the developed electrode on the EDM machining is also examined by changing the EDM process parameters (discharge current, pulse-on time and voltage). The composite electrode characterization results indicated that as the percentage of CNT increases from 0.35 to 1.05 vol%, the density reduced and electrical resistivity increased due to the rise in porosity. Performance review of CNT-infused electrodes during EDM machining revealed a higher Material removal rate (MRR) and good surface finish than the Cu electrodes due to high discharge energy and enlargement in the spark gap. However, Cu/CNT electrodes wore out faster than Cu electrodes by 90%, possibly due to the reduction in thermal conductivity induced by porosity effects. Comprehensively, although the addition of CNT affected the mechanical attributes of the electrode, it offered significantly better output (MRR and Surface finish) than the Cu electrode with limitations on electrode wear.