A Comprehensive Study on Processing Ti–6Al–4V ELI with High Power EDM

Abstract

Electrical Discharge Machining (EDM) consists of a non-conventional machining process, which is widely used in modern industry, and especially in machining hard-to-cut materials. By employing EDM, complex shapes and geometries can be produced, with high dimensional accuracy. Titanium alloys, due to their unique inherent properties, are extensively utilized in high end applications. Nevertheless, they suffer from poor machinability, and thus, EDM is commonly employed for their machining. The current study presents an experimental investigation regarding the process of Ti–6Al–4V ELI with high power EDM, using a graphite electrode. Control parameters were the pulse-on current (Ip) and time (Ton), while Machining performances were estimated in terms of Material Removal Rate (MRR), Tool Material Removal Rate (TMRR), and Tool Wear Ratio (TWR). The machined Surface Roughness was calculated according to the Ra and the Rt values, by following the ISO 25178-2 standards. Furthermore, the EDMed surfaces were observed under optical and SEM microscopy, while their cross sections were also studied in order the Average White Layer Thickness (AWLT) and the Heat Affected Zone (HAZ) to be measured. Finally, for the aforementioned indexes, Analysis Of Variance was performed, whilst for the MRR and TMRR, based on the Response Surface Method (RSM), semi-empirical correlations were presented. The scope of the current paper is, through a series of experiments and by employing statistical tools, to present how two main machining parameters, i.e., pulse-on current and time, affect major machining performance indexes and the surface roughness.

Experimental Investigations and Effect of Nano-Powder-Mixed EDM Variables on Performance Measures of Nitinol SMA

“…To improve machining, one effective method is to add nano-powders to the dielectric fluid in the proper quantity [ 17 , 18 ]. By enhancing spark discharge, the particle’s inclusion in the dielectric fluid lowers the breakdown strength and enhances the igniting mechanism [ 19 ]. In turn, this improves the process’s capacity for cutting.…”

Performance evaluation of electric discharge machining of titanium alloy-a review

“…Karmiris-Obrataski et al [20] used a graphite electrode and a high-power EDM during the processing of material Ti-6Al-4V ELI. ANOVA model revealed that both the pulseon time and current have a strong influence on the MRR with contributions of 61.65% and 21.94%, and provided some combinations of machining parameters that result in a lower TWR and thus lower machining costs, making the machining economically feasible.…”

Experimental investigation on the performance variations of three different work piece materials in EDM with variation of thermo-physical properties

“…As a result of which, the electrical energy is converted into heat energy. The temperature attained on the surface of the material where the spark hits, is of the order of 6,000-12,000ºC has identi ed by Karmiris-Obratanski et al [4]. As a result of which some part of the material is melted and evaporated.…”