# Parametric Investigation of Die-Sinking EDM of Ti6 Al4V Using the Hybrid Taguchi-Rams-RATMI Method
## 1 Introduction  
Because it can precisely mill hard materials and intricate forms, electrical discharge machining (EDM) has gained popularity. Because EDM uses electrical discharges insteadof standard machining processes to remove material from the workpiece, it is especially effective on materials that are challenging to machine. Titanium Grade 5 alloy (Ti6 Al4V), renowned for its remarkable strength, low density, and superior corrosion resistance, is one such material. Ti6 Al4V is the perfect material for important applications in the aerospace, biomedical, and automotive sectors because of these qualities [1]. Its great strength and low heat conductivity, however, provide serious difficulties for traditional machining methods, resulting in quick tool wear and subpar surface smoothness [2]. Ti6 Al4V, an \(\alpha+\beta\) titanium alloy with 4% vanadium and 6% aluminum, provides a special blend of corrosion resistance and mechanical qualities [3]. The aerospace industry uses this alloy extensively for items like fasteners, turbine blades, and aircraft structural elements for its high strength-to-weight ratio and superior performance at high temperatures. In the biomedical field, Ti6 Al4V is extensively used for medical implants and prosthetics because of its biocompatibility and resistance to body fluids [4]. Despite its desirable properties, the machinability of Ti6 Al4V is a major concern. Traditional machining methods often struggle with rapid tool wear, high cutting forces, and the generation of excessive heat, which can adversely affect the material's microstructure and mechanical properties [5]. By using thermal energy to erode material without the tool and workpiece coming into close touch, EDM provides a competitive substitute. As a consequence, there are fewer mechanical stresses and difficult-to-reach places and complex geometries may be machined [6]. The selection of electrode material and process parameters has a considerable impact on EDM efficacy. Critical elements that impact the effectiveness of the EDM process include electrode wear, surface roughness, material removal rate (MRR), and dimensional accuracy. Copper, graphite, and copper-tungsten are a few of the electrode materials that have been researched to maximize EDM performance for various workpiece materials, including Ti6 Al4V [7]. Copper is a versatile material with high electrical and thermal conductivity, making it ideal for EDM processes. Its high electrical conductivity ensures stable sparking, reduces electrode wear, and maintains surface integrity. Copper electrodes are easy to machine, allowing for intricate shapes. Despite moderate wear resistance, copper electrodes are crucial in EDM due to potential dimensional inaccuracies and increased costs. Despite challenges like electrode wear and cost, copper electrodes are suitable for the precision machining of complex geometries and high-quality surfaces. Copper electrodes offer superior surface finish and dimensional accuracy due to their high conductivity, resulting in precise control of spark energy. They are versatile and suitable for both roughing and finishing operations in the EDM process. Copper also works well with various dielectric fluids, enhancing flushing efficiency and reducing the risk of arcing and short circuits. Overall, copper electrodes are ideal for high-quality applications. Copper electrodes are more expensive than graphite electrodes in high-energy EDM processes, leading to faster wear and increased operational costs. They are also more prone to contamination, leaving residue on the workpiece surface, which may require additional cleaning processes, especially in applications with strict cleanliness standards. These factors can be particularly significant for large-scale or long-duration EDM operations. Copper electrodes are utilized in various industries, including tool and die making, aerospace, medical devices, and automotive.