Characterization of Surface Topographies Generated using Circular- and Cylindrical-Face EDT

Abstract

Large area texturing using EDT is challenging due to surface damage resulted from inefficient discharges, such as arcs and short-circuits. Also, three-dimensional analyses of surface topography generated during electrical discharge texturing (EDT) are scarcely performed in the available literature. Therefore, in this work, two modes of EDT were developed for large area texturing based on the mode of electrode movement resulting in texture generation on work surfaces: circular-face EDT (CirEDT) and cylindrical-face EDT (CylEDT), and the generated surface topographies are characterized in terms of topography images, areal texture parameters, and scanning electron microscopy images. Parametric analyses are also performed to study the influences of the operating parameters, such as discharge current, pulse on-time, and peripheral velocity, on different areal texture parameters. Topography analyses reveal that these surfaces have a characteristic stochastic distribution of microstructures in shape, size, and location. Height parameter analyses reveal that CylEDT surfaces are twice positively skewed and have a higher kurtosis as compared to the CirEDT surfaces. Spatial parameter analyses reveal that both surfaces display dominance of isotropic nature and non-directional structures. CirEDT surfaces have higher lubricant retention capacity, but lesser wear volume available for running-in period as compared to CylEDT surfaces, as per volume parameter analyses. Discharge current and pulse on-time are identified as the significant parameters influencing the majority of the areal texture parameters analyzed. SEM analysis revealed that CylEDT results in a textured surface with sea-wave-like structures, whereas CirEDT results in a textured surface with lunar-craters-like structures.