Effect of wire material and discharge energy on productivity and surface integrity of WEDM-processed Inconel 718

The current work aims to study the influence of discharge energy and debris accumulation on wire break failure and surface integrity aspects like surface roughness, subsurface hardness, and geometrical errors during the wire EDM of Inconel 718. The responses considered for analysing the geometrical accuracies are flatness error, roundness error and cylindricity error. Four different wire electrodes were considered for the study based on the wire strength and coatings, namely hard zinc coated brass, half-hard zinc coated brass, hard uncoated brass, and half-hard uncoated brass wire electrodes. The geometric accuracy of the machined parts is closely related to the choice of wire electrode. High-tensile strength hard wires were observed to machine the surfaces with maximum accuracy. Also, the zinc coated wires were observed to cut faster compared to the uncoated wire electrodes. The study revealed that there exists a strong influence of discharge energy on the surface integrity of wire electric discharge machined surface. The zinc and copper elemental contamination was minimal for uncoated wire electrodes at lowest discharge energy mode. Wire wear phenomena was analysed for both coated and uncoated wires. Discharge energy had a significant impact on the electrode wear of coated and uncoated wire electrode