Influence of discharge energy on machining characteristics in EDM

Abstract

The machining characteristics of electrical discharge machining (EDM) directly depend on the discharge energy which is transformed into thermal energy in the discharge zone. The generated heat leads to high temperature, resulting in local melting and evaporation of workpiece material. However, the high temperature also impacts various physical and chemical properties of the tool and workpiece. This is why extensive knowledge of development and transformation of electrical energy into heat is of key importance in EDM. Based on the previous investigations, analytical dependence was established between the discharge energy parameters and the heat source characteristics in this paper. In addition, the thermal properties of the discharged energy were experimentally investigated and their influence on material removal rate, gap distance, surface roughness and recast layer was established. The experiments were conducted using copper electrode while varying discharge current and pulse duration. Analysis and experimental research conducted in this paper allow efficient selection of relevant parameters of discharge energy for the selection of most favorable EDM machining conditions.

Modelling and investigating the effect of input parameters on surface roughness in electrical discharge machining of CK45

“…Moreover, surface roughness of the machined piece greatly influences the quality of the generated pieces (machined parts) in the moulding industry. One of the methods which is appropriate for machining of the alloys and is not dependant on the hardness and strength of the workpiece is electrical discharge machining (EDM) [1]. EDM is the process of machining electrically conductive materials by using precisely controlled sparks that occur between an electrode and a workpiece in the presence of a dielectric fluid.…”

Optimization of process parameters for WEDM of Inconel 825 using grey relational analysis

“…heat affected zone (HAZ) and recast layer (RL). By the application of gap voltage the work material surface reached the melting temperature and re-solidified on the work surface and recast layer formed due to the deposition of the effected material in the form of macro ridges and pull-out material (Çaydas and Ay, 2016;Gostimirovic et al, 2012). Below the recast layer, there is heat-affected zone which is formed due to less temperature of the work surface below the recast layer (Çaydas and Ay, 2016).…”

Surface layer of Inconel 718 after WEDM process

“…Roztopiony metal, który nie został usunięty z powierzchni krateru, ponownie na nim zastyga, tworząc cienką warstwę (rzędu kilku -kilkunastu mikrometrów) o zmienionych własnościach w stosunku do materiału rdzenia. Podczas obróbki występują setki wyładowań elektrycznych, które tworzą charakterystyczną dla procesu WEDM strukturę geometryczną powierzchni (SGP), formowaną poprzez nakładanie się kraterów z pojedynczych wyładowań [2,3,7]. Na podstawie przeprowadzonych pomiarów SGP stwierdzono, iż w zależności od zastosowanych parametrów obróbki następuje zmiana struktury geometrycznej powierzchni a w szczególności następuje zmiana parametrów wysokościowych, dlatego w dalszej analizie struktury geometrycznej powierzchni skoncentrowano się na parametrze chropowatości Sa.…”