CHALLENGES TO MINIATURIZATION IN MICRO EDM

摘要

Factors which influence on the limit of miniaturization in micro EDM were discussed. To minimize the discharge energy maintaining machining stability, the electrostatic induction feeding method was developed. A tungsten carbide micro rod of 1.3 μm in diameter was obtained. Under the influence of the tensile residual stress generated by EDM, the micro beam machined is bent to the side where EDM is performed. When the center of the micro rod machined is off-centered from the center of the material rod in which residual stress is generated by the wire-drawing process prior to electrical discharge machining, this residual stress causes deformation of the micro rod after machining. Releasing the residual stress, by annealing is effective for avoiding the deformation. WC grain size influences the minimum machinable diameter of cemented tungsten carbide rods.