Super-finished Surfaces using Meso-micro EDM

Abstract

A novel stochastic orbiting strategy combined with extremely low stray capacitance sinking EDM machine offers the capability to achieve super-finished surfaces (Ra<0.1μm) without pre-polishing of the copper tool electrodes. Surface defects such as inhomogeneity, cracks, arc spots and black spots have been analysed and reduced, while improving material removal rate with lower tool wear. Super-finished surfaces thus generated have uniform white layer (re-solidified layer) with an average thickness below 1μm. Unlike mirror finishing using EDM with powder mixed dielectric, absence of the additives in dielectric results in smaller gap width during finishing, delivering sub-micron accuracy of the machined features. With the tool electrodes machined using conventional machining techniques such as milling, turning or wire-EDM having surfaces with Ra≤0.2μm, advamcements of the work offers manufacturing industry an economic and energy efficient super-finishing process, especially in meso-micro scale.