# Parametric Investigation of Die-Sinking EDM of Ti6 Al4V Using the Hybrid Taguchi-Rams-RATMI Method
## 1 Introduction
In Ti6 Al4V ELI (Grade 23), [PERSON] et al. 's [12] investigation discovered a direct relationship between discharge current and surface morphology, MRR, and surface polish. Superior surface quality is achieved with lower current intensity and higher discharge energy, which diminishes the surface finish. Gap voltage, peak current, and pulse-on time were shown to be the most efficient parameters in [PERSON] and [PERSON]'s [13] experiment on Ti-5 Al-2.5 Sn alloy electro-discharge machining. This suggests that RSM combined with the GRA method may efficiently handle multi-response optimization issues in EDM. The goal of [PERSON] and [PERSON]'s study [14] was to improve the surface finish on Ti6 Al4V by optimizing EDM settings. They tested with pulse time, pulse off, and current using spark erosion EDM (EDM). The findings indicated that pulse-off time is the factor that has the greatest impact on surface roughness, with the current coming in second. Using the L-9 orthogonal array, [PERSON] and [PERSON] [15] optimized die-sinking EDM on Ti6 Al4V. Microcracks and a recast layer were discovered on the machined surface by SEM imaging and XRD investigation. Surface roughness, TWR, and MRR were the ideal process variables. The structure of the work material was changed by thermal heating and cooling. In their study, [PERSON] et al. [16] investigated the best parameter settings to get high-quality results while utilizing a brass electrode for electrical discharge machining titanium Grade 6 alloy. Grey relational grade and relative closeness coefficient improvements were observed in confirmation trials. According to [PERSON] and [PERSON]'s [17] study, voltage is the most important input parameter for output performance parameters, improving metal removal rate, TWR, and overcut during micro-electric discharge machining (micro-EDM) of Ti6 Al4V alloy. In Ti6 Al4V planetary electrical discharge machining, [PERSON] et al. discovered that the duty factor selection is critical and that pulse-ON time and current had a substantial influence on reactions [18]. For a greater wear ratio and a lower TWR, the tool electrode should have a negative polarity. The study shows that total wire resistance in Ti6 Al4V planetary EDM is influenced by machining settings and tool actuation, with copper electrodes exhibiting reduced material loss [19]. The electrode material has a considerable impact on the ideal process parameters, according to [PERSON] et al. 's [20] work on micro EDM. Taguchi-MOORA, which is based on ratio analysis, achieves high machining quality and precision. In research by [PERSON] and [PERSON] [21], MRR increased with peak current, gap voltage, pulse-on time, and dielectric fluid flow pressure when die-sinking EDM was used to machine Ti6 Al4V. Alongside these factors comes an increase in surface roughness. On the machined surface, the scientists also discovered craters and tiny fissures. [PERSON] et al. 's [22] study of titanium alloy machining techniques identified low thermal conductivity and excessive heat generation as EDM process problems, with hybrid approaches becoming more popular. According to [PERSON] et al. 's [23] study, electrode selection has a major influence on the effectiveness of electro-displacement machining (EDM) on Ti6 Al4V. Copper electrodes that have undergone cryogenically treated conditions exhibit improved performance, lower SCD, and higher WLT. Graphite powder was added to kerosene dielectric liquid in [PERSON] and [PERSON]'s [24] study to improve EDM performance in the aerospace sector. This resulted in higher MRR, surface roughness, and lower relative wear, demonstrating the suitability of graphite powder to EDM applications. [PERSON] et al. [25] used orthogonal array and grey relational analysis to optimize the EDM process for titanium alloy, resulting in improved performance and optimum parameters. In the research on EDM in Ti6 Al4V ELI processing, [PERSON] et al. [26] discovered that machining parameters had an impact on MRR, TMRR, and TWR, with pulse-on current having a greater influence.