Assessing the Effects of Uncoated and Coated Electrode on Response Variables in Electrical Discharge Machining for Ti-6Al-4V Titanium Alloy

Abstract

The coated electrodes with high heat resistant alloy materials can considerably improve the efficiency of electrical discharge machining (EDM) process. In the present study, the influence of Aluminum Chromium Nickel Coated aluminium electrode was investigated on the quality criteria using EDM while machining Titanium alloy (Ti -6Al-4V). The peak current, gap voltage and pulse-on time were used as input parameters to analyze the material removal rate, tool wear rate and surface roughness under the L16 based Taguchi method and ANOVA method. It was observed that Aluminum Chromium Nickel (AlCrNi) coated electrode could produce higher material removal rate (MRR), lower of tool wear rate (TWR) and surface roughness (Ra) than uncoated electrode. Compared with EDM with uncoated electrodes, the quality indicators in EDM with coated electrode are better, namely 8% higher MRR, the lower TWR and Ra are 8% and 24%, respectively. The better surface finish was also observed with the coated electrode due to its thermal conductivity.

Multi-criteria decision making in electrical discharge machining with nickel coated aluminium electrode for titanium alloy using preferential selection index

“…And this is the main cause which reduces machining productivity, and TWR is also reduced at the same time. Compared with EDM using Al electrode, MRR and TWR were more strongly affected by the change of T on with Nickel coated electrode [48] because the Nickel coated layer is strongly influenced by T on .…”

“…The shape of electrode is cylindrical with 10 mm in diameter and 35 mm in length, as shown in 1 and Figure 2 shows EDAX of copper coating and it was evident that presence of copper material in coating. The dielectric solution used in the present study was HD-1 oil [48]. This is the type of oil used quite commonly in the fields of pulse machining today in Vietnam.…”

“…Therefore, electrode and work-piece material which are melt and vaporized also increase. Comparing EDM using Aluminium (Al) electrode, effects of curent (I) to quality criteria in EDM using coated electrode is better and MRR in EDM using coated Al electrode is higher and TWR is smaller [48]. This shows that Nickel coated layer affects well to machining efficiency using EDM.…”

“…This problem comes from the change of voltage (U), it will affect to energy of sparks and energy which break the insulation of the dielectric solution, and this energy increases when voltage (U) increases. However, increase of voltage (U) afects badly to EDM machining process using coated electrode because increase of MRR is smaller than increase of TWR [48]. So, electrode life will be decreased, machining accuracy is low.…”

Recent Trends and Developments in the Electrical Discharge Machining Industry: A Review

“…However, the prevailing number of studies related to ET is aimed at reducing their wear or compensating for modification. It is possible to single out the main directions of modification: selection of new nontraditional materials [17,103,137,138], processing or coating [17,97,98,[139][140][141], creation of non-traditional geometric shapes [49,137,[142][143][144], using modern methods of additive manufacturing [145][146][147][148], creation of original structures [146,148], etc.…”