SWOT Analysis of Electrical Discharge Coatings: A Case Study of Copper Coating on Titanium Alloy

Abstract

The electrical discharge machine (EDM) has been one of the most widely used non-traditional machines in recent decades, primarily used for machining hard materials into various complex shapes and different sizes and, nowadays, used for surface modifications/hard coatings. In this study, the SWOT (strengths, weaknesses, opportunities and threats) of electrical discharge coating was analyzed by conducting a case study. For the purpose of the case study, copper was deposited on the titanium alloy surface (Ti6Al4V). Three electrodes of different copper alloy materials, viz., brass, bronze and copper, were selected for coating the Ti6Al4V surface. Input parameters such as current, pulse-on, pulse-off, flushing pressure and the electrode material were optimized to develop a uniform coating. Experiments were designed according to the L18 orthogonal array, and among them, the samples that showed proper coating, as seen with the naked eye, were selected for morphological and elemental analyses by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX. Further, the output responses, viz., the material deposition rate (MDR), electrode wear rate (EWR), surface roughness (SR), elemental data (copper (Cu) and zinc (Zn)) and coating thickness (CT), were considered for the optimization of coatings. Implementing the Technique for Order Performance by Similarity to Ideal Solution, copper coating with a thickness of 20.43 µm, developed with an MDR with input parameters of 20 A current, 600 µs pulse-on, 120 µs pulse-off, 0.5 bar flushing pressure and the brass electrode, was selected as the optimum coating. The most influential parameters in this coating process were the current and pulse-on time. In this study, a SWOT table was developed to depict the strengths, weaknesses, opportunities and threats of electrical discharge coating.