FINITE ELEMENT MODELLING OF HYDRAULIC MECHANICAL REMOVAL MECHANISM AT ULTRASONICALLY AIDED EDM FINISHING

Abstract

The paper deals with finite element modelling (FEM) of material removal mechanism due to ultrasonically induced cavitation in the working gap at finishing modes of electrical discharge machining. The peaks of machined microgeometry are removed, having lower shearing resistance than the other parts of microgeometry, thus the surface roughness being reduced. Experimental data are presented that indicated an optimum value of power consumed on ultrasonic chain, including the electrode-tool, at which a minimum value for surface roughness was obtained. This corresponds to a pressure developed by collective implosion of the gas bubbles from the working gap, produced by shock waves oriented along the working gap, parallel to machined surface. This ultrasonic effect is considered a cycle pulse fatigue load on the flanks of microgeometry profile.