Formation and Optimization of Electrical Discharge Coatings Using Conventional Electrodes

Abstract

An emerging topic is electrical discharge (ED) coating with its application on complex shapes and cavities to repair components or act as functional coatings. Because it is a variant process of an electric discharge machine (EDM) with the ability to coat on electrically conductive substrates, there is a possibility that next-generation electrical discharge machining components may exploit the attachment phenomenon to enhance recast layer properties. Previously, researchers have obtained ED coating by mixing the powder in a dielectric medium and/or by using powder metallurgy electrodes. In this work, primarily, an insight in the formation of ED coating on-die sinks electrical discharge machine, using conventional electrode materials viz., bronze on titanium alloy (Ti-6Al-4V) is made. The bronze electrode on the titanium substrate obtained a crack-free copper coating of ~20 microns thickness. In order to perform the experiments, three combinations were made using five parameters: current (Amps), ton (µs), Toff (µs), duty cycle (%), and flushing pressure as constant (bar). After obtaining the coating, a combination of input parameters was selected by optimizing the output performance parameters, viz., the electrical discharge deposition rate, coating thickness, micro-cracks, and elemental coating composition. Secondarily, different optimization techniques viz., grey relational analysis, the technique for order of preferences by similarity to ideal solution, −nD angle method and information divergence method were implemented to find out the suitable combination of parameters where the latter two methods were introduced for the first time in this area of EDM optimization. A study was conducted to check whether the latter two methods are optimization techniques or multi-criteria decision-making techniques. The optimization of existing reactor types and the development of new reactors in wastewater treatment through EDC, by which energy could be saved by replacing the conventional techniques.

Evaluation of Bronze Electrode in Electrical Discharge Coating Process for Copper Coating

“…The three levels of EDM machining process parameters selected are shown in Table 2 . Output parameters such as surface quality, surface topography and homogeneity of the coatings rely on the input process parameters, viz., current, Ton, Toff and temperature, as shown in Table 2 [ 19 ]. Taguchi L9 design was followed to prepare the combination of parameters [ 30 , 31 ] as shown in Table 2 .…”

“…This method consists of alternatives in the rows and attributes in the columns. The matrix format can be expressed as follows [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. …”

“…Hsu et al [ 18 ] varied input parameters of the EDM, viz., material removal rate (MRR), surface roughness (Ra) and electrode wear rate (EWR), to improve the surface finishing. Here, oxygen plasma etching treatment was performed to decrease the surface roughness [ 19 ]. In order to further increase the surface characteristics, physical vapor deposition (PVD) was performed to coat TiN.…”

Electric discharge coating process: a critical review with potential application

“…Some researchers developed a hard carbide layer using multi-layer electrodes. Maddu J et al [34] reported a 20 μm thick copper coating with a conventional copper electrode and optimized the process parameter with grey relational analysis, and the result shows micro-cracks, coating thickness, and material deposition increases with the increase in current and pulse duration. Muralidharan B et al [35] experimentally investigate electric discharge deposition using a solid electrode with magnetic field, and the results show deposit increased by magnetic field effect.…”

Investigating Technological Parameters and TiN-Coated Electrodes for Enhanced Efficiency in Ti-6Al-4V Micro-EDM Machining

“…Importantly, the characteristics of coatings on electrode surfaces wield substantial influence over machined surface topography after EDM, with grain size playing a pivotal role in determining indentation size [27]. In parallel, the interplay of technological parameters such as U, I, and Ton on quality indicators in EDM with coated electrodes requires thorough elucidation for the practical application of this technology [28].…”