Surface integrity of electrodischarge machined cavities for different depths and radii

Abstract

With the increasing need to reduce manufacturing time, the demands on machining operations on hardened steel have greatly increased. Due to higher mechanical forces needed to machine hardened steel, tools tend to wear out quicker, increasing costs. One alternative that has been applied is electrodischarge machining, which is widely applied due to its versatility and possibility of machining complex shapes on any conducting material, independent of its mechanical properties. However, due to the higher temperatures resulting from the electrical discharges, the machining conditions greatly affect the surface integrity, causing undesirable effects that may cause component failure during service. In addition, the electrode characteristics, such as shape, material and geometries, may greatly affect the machined surface, leading to greater or smaller machined surface damage. In this context, this work presents an evaluation of the surface integrity of AISI P20 mold steel after machining, using electrodes with different radii and machining depths, statistically evaluated through analysis of variance. Different regions of the cavity were evaluated, and results showed that machining depth had significant effect on the heat-affected zone thickness.