Rachakonda Ranjith Kumar’s scientific contributions

This study analyses the EDM process of AISI D2 steel with copper tungsten electrode along with Al2O3 powder mixed in sunflower oil as a dielectric fluid in place of EDM oil. AISI D2 steel is predominantly used in the manufacture of precision components of dies, press tools, automobiles, aircraft and space equipment. For that reason, it has been selected as work piece material. Based on the high conductivity nature of electrical and thermal characteristics of copper tungsten, it is used as an electrode in the process. Due to the easy availability and affordability, Al2O3 particles of 60 nano meter size is taken as catalyst for mixing with the sunflower oil and used as an alternate dielectric fluid in place of EDM oil. In order to reduce the harmful effects on the environment produced by the gases due to EDM oil, a vegetable oil namely, sunflower oil is used in its place. Flash point, fire point is higher than 300°C in sunflower oil when compared to conventional EDM oil. It is also eco-friendly and biodegradable. Input parameters of pulse interval, pulse duration, discharge voltage and peak current are compared with various output parameters of the process, namely, electrode wear rate, surface roughness and material removal rate. Experiments are conducted using Taguchi L9 experimental design and the effect of process input values over the output process response are analyzed using ANOVA method. The analysis leads to the conclusion that powder mixed EDM process (PMEDM), in which Al2O3nano particles mixed with sunflower oil yields a minimum surface roughness due to the better heat absorption. More removal of material along with a lesser tool wear is also noticed. Nano particles of Al2O3 improved the surface finish due to the abrasive action of the lowest discharge gap between particles.

A prodigious research work is being effectuated to endorse the optimal machining parameters while entailing present day machining techniques to bring outclassy products. This research work insisted on suggesting the optimum process parameters of die sinking EDM with 8mm diameter copper electrode during machining AISI D2 steel using TOPSIS.Taguchi’s L9 Orthogonal Array method was adopted to design 9 experiments in total and Pulse on time (T on ), Servo voltage (SV) and Peak current (I P ) are chosen as input parameters. Three levels of each parameter were selected for designing the experimentation. EDM oil which is a synthetic oil is selected as dielectric and all the values of Material Removal Rate (MRR), Tool Wear Rate (TWR) and Surface Roughness (SR) for each experiment were noted as the output responses. Analysis of Variance (ANOVA) was done to recommend the impact of each input parameter on output responses. Analytical Hierarchy Process (AHP) was used to select the weightage of each response and then Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) which is a multi-criteria decision analysis method, was accompanied for determination of ideal parameters for machining AISI D2 steel. Eventually it is descried that the amalgamation of level 3 of pulse on time, level 3 of Peak Current and level 3 of servo voltage propounds the optimum result.