Modeling of Thermal Spalling During Electrical Discharge Machining of Titanium Diboride

Abstract

Erosion in electrical discharge machining has been described as occurring by melting and flushing the liquid formed. Recently, however, thermal spalling was reported as the mechanism for machining refractory materials with low thermal conductivity and high thermal expansion. The process is described, here, by a model based on a ceramic surface exposed to a constant circular heating source which supplies a constant flux over the pulse duration. The calculations were based on TiBz mechanical properties along a and c directions. Theoretical predictions were verified by machining hexagonal TiBz. Large flakes of TiBz with sizes close to grain size and maximum thickness close to the predicted values were collected, together with spherical particles of Cu and Zn eroded from cutting wire. The cutting surfaces consist of cleavage planes sometimes contaminated with Cu, Zn, and impurities from the dielectric fluid. [

Parametric analysis on electrochemical discharge machining of silicon nitride ceramics

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Removal Mechanism of Glass Using Lathe-Type Electrochemical Discharge Machine

“…(1) Then sodium silicate is dissolved into the electrolyte. In addition, bits of the workpiece surface are sometimes sublimed and/or spalled 16) . In the lathe-type ECDM, the tool electrode scratches the rotated workpiece so that the scraping off of sodium silicate is conceivable.…”

Application of new tool material for electrical discharge machining (EDM)

“…Material with high hardness and high strength such as super alloys, composites, advanced ceramics etc with close precision and surface finish can be done by EDM satisfactorily, where the traditional machining fails (Petrofes 1988;Gadalla et al 1991;Ho and Newman 2003;Khanra and Khanta 2005;Khanra et al 2006). In EDM, the tool and the workpiece (WP) are connected to two electrodes and separated by a dielectric fluid.…”