# Parametric Investigation of Die-Sinking EDM of Ti6 Al4V Using the Hybrid Taguchi-Rams-RATMI Method
## 5 Conclusions  
Using a hybrid technique that combines Taguchi RAMS-RATMI optimization methodologies, this work gives a thorough parametric examination of the die-sinking EDM process applied to the Ti6 Al4V alloy. The main goal of the EDM process optimization was to obtain increased machining performance and surface integrity of Ti6 Al4V. For high-precision and high-performance manufacturing applications, the optimized process parameters obtained via this study greatly improve machining performance, surface integrity, and operational dependability. Important findings from this research include the following:  
* The RATMI majority index (Ei) was found to be higher in R1 than in R12. To optimize machining characteristics, the Ton of 500 us, duty cycle of 8%, peak current of 40 Amp, and voltage of 20 V can be considered. The main effect plot of means for the RATMI majority index (Ei) shows that the maximum value fetched in the same factor configuration should be considered. * The ANOVA results show that all the machining parameters are significant in achieving the desired output characteristics. Peak current, with a 51.77% contribution, maximizes MRR and the depth of cut while minimizing surface roughness and TWR, thereby enhancing the machining output characteristics. Also, the residual plots show a good fit of the experimental data. * The study reveals that the majority index (Ei) decreases during medium-level machining settings while increasing at lower-level settings, resulting in lower MRR and high surface roughness values. This phenomenon is also observed in surface plots, with the majority index decreasing in deeper areas and increasing in higher areas. * The surface of Ti6 Al4V is impacted by EDM using a copper tool. Small and large craters are present due to spark erosion, resulting from localized melting and vaporization. R12 has higher surface roughness than R1 due to irregular craters and molten metal droplets. The roughness can vary depending on EDM parameters, with higher discharge energy generally resulting in higher surface roughness. * SEM micrographs show the recast layer formed on the surface of molten material due to solidification. EDM settings affect the recast layer's thickness, with thinner layers often due to decreased energy levels. Inhomogeneous heat flow, metallurgical transformations, and plastic deformation are often encouraged by EDM operation, leading to residual tension and surface cracking. A heat-affected zone beneath the recast layer undergoes structural changes and thermal pressures without melting. * Surface morphology of EDMed Ti6 Al-4V specimens with copper electrodes shows poor surface integrity, including fractures, microcracks, globules, pockmarks, and a white layer. The degree of surface imperfections varies depending on electrode material and spark energy input. This study suggests future research to improve the process efficiency, enhance material properties, and explore alternative dielectric fluids, tool electrode materials, and electrode coatings. It suggests hybrid and sequential EDM processes, combining EDM with other techniques for enhanced performance, and focusing on precision and surface quality in micro-components and medical implants. Real-time monitoring systems, environmental and economic aspects, life cycle analysis, cost-benefit analysis, and customization for specific applications can encourage interdisciplinary research and industry-academia partnerships. Conceptualization, C.S. and P.P. ; data curation, A.B. and S.P. ; formal analysis, A.B. and S.P. ; investigation, C.S., S.P., K.K. and P.P. ; methodology, C.S. and P.P. ; resources, P.P. ; software, S.P. ; supervision, K.K. ; validation, A.B. ; writing--original draft, C.S., A.B., S.P. and K.K. ; writing--review and editing, A.B., S.P. and K.K. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable.