# Parametric Investigation of Die-Sinking EDM of Ti6 Al4V Using the Hybrid Taguchi-Rams-RATMI Method
## 1 Introduction
They are used in tool and die making for producing precision components, in aerospace for high-strength alloys, in medical devices for fabricating complex shapes and fine features in biocompatible materials, and in automotive for machined components like fuel injection nozzles, valve seats, and transmission parts. Copper electrodes ensure high precision and surface finish in these applications. An experimental investigation on Ti6 Al4V was carried out by [PERSON] et al. [1] to assess the effect of machining factors on wire EDM. The findings demonstrated that peak current and pulse-off duration were the primary factors influencing surface roughness when utilizing the GRA optimization approach. As the peak current increased, so did the surface roughness. Peak current and pulse-off time were found to be the two main factors that influenced MRR. While machining Ti6 Al4V, [PERSON] et al. [2] carried out an experimental optimization of EDM die-sinking electrode materials, including copper, brass,and graphite. They designed and machined electrodes using statistical techniques, noting surface roughness, fluctuations in surface hardness, and dimensional stability. The results showed graphite electrodes produced a better surface finish with minimal dimensional variation, indicating higher resistivity toward current. The depth of machining significantly impacted surface hardness variations post-machining. Using Ti-5 Al-2.5 Sn alloy as the workpiece, [PERSON] and [PERSON]'s [3] experiment investigated the effects of several electrode types (copper, brass, and zinc) on the EDM process. According to the results, copper electrodes generated a smoother surface and exhibited less tool wear than brass and zinc electrodes, which both achieved greater MRR. According to research by [PERSON] and [PERSON] [4], multi-performance parameters in titanium alloy drilling are highly impacted bypulse-on time. The investigation discovered that the genetic algorithm was the most efficient, improving quality attributes by 59%. The effects of machining factors on tool wear rate (TWR) during EDM of Ti6 Al4V were investigated by [PERSON] et al. [5]. They examined the ideal circumstances for the lowest possible TWR and discovered that cryogenic copper had a greater TWR than untreated copper, with more noticeable impacts on current, pulse-on time, and tool electrode type. The effect of EDM on surface integrity in Ti6 Al4V has been investigated by [PERSON] et al. [6]. Peak current improves MRR, the TWR, and Ra, while longer pulse-on times shorten the pulse and degrade the surface quality. EDM produces oxides and carbides, which increase wear resistance. Using WEDM, [PERSON] and [PERSON] et al. [7] tested the fracture toughness of compact tension specimens made of Ti6 Al4V. The average toughness value, 111.82 MPa.m0.5, was 4.4% less than what was stated in the literature. The fracture surfaces met the criteria for plane strain, suggesting that compact tension specimens may be safely pre-cracked by WEDM in order to measure the fracture resistance of Ti6 Al4V. The work by [PERSON] et al. [8] uses a graphite tool electrode with negative polarity to optimize the EDM parameters for Ti6 Al4V. Surface roughness, variation between entrance and exit, titanium machining rate, and graphite wear rate are all heavily influenced by electrical factors. Peak current and pulse-on time were identified by [PERSON]'s [9] research as the two main influencing variables in EDM machining using a copper tool electrode. Maximal MRR, minimum TWR, and minimum hole taper were the ideal characteristics, improving mathematical models for micro-EDM performance. Current and pulse-on time were determined to be essential factors in [PERSON] et al. 's [10] investigation of sink electric discharge machining of Ti6 Al4V, with pulse-on time having the most significant impact--apart from MRR. According to [PERSON] et al. 's [11] research, MRR is greatly impacted by spark-on time, discharge current, and tool diameter when it comes to machining reactions in EDM for Ti6 Al4V alloy.