Dielectric Pressure Research Articles

Si3N4-TiN rotary EDM optimization by Mo-Jaya algorithm with Pareto optimal solution, analysis of micro-structural and geometrical tolerances

Research into rotary electrical discharge machining on high temperature with biomedical application Si3N4-TiN ceramic composite is presented in this paper. Current (I), pulse on time (Ton), pulse off time (Toff), dielectric pressure (DP), speed and spark gap voltage (Sv) are some of the many performance characteristics. Among the factors taken into account is the material removal rate, surface roughness, electrode wear rate, cylindricity, perpendicularity, top radial overcut, bottom radial over cut and run out. Multiple parameter combinations were validated experimentally and the resulting reactions were examined. Mean effects analysis and regression analysis are used to investigate the impacts of individual parameters. To comprehend the instantaneous behavior of the replies, multi-objective Jaya optimization is utilized to optimize the responses simultaneously. The multi-objective problem's outcomes are shown in 3D charts, with each showing the Pareto optimal solution. From this real conclusion, the optimal combinations of answers are extracted and reported. The aggregate optimization result was also shown, which factored in all eight responses. MRR of 0.238 g/min was obtained which is a 10.6% improvement from the experimental values. Electrode wear of 0.0028 g/min was obtained showing a 6.6% reduction. Similarly reduction in values of Surface roughness, top radial overcut and bottom radial over cut, Circularity, Perpendicularity, run out was observed and the percentages are 3.4, 4.7, 4.5, 7.8, 10.0 and 10.53 respectively. Details on the structural and morphological examinations of the various surface abnormalities that occur during the process have been presented.

Simultaneous multi-response Jaya optimization and Pareto front visualization in EDM drilling of MoSi2-SiC composites

This study delves into the EDM of the MoSi2-SiC intermetallic ceramic composite. Dielectric pressure (DP), spark gap voltage (Sv), and spark gap speed (v) are all variables that affect the quality of a spark. Many performance metrics, such as material removal rate, surface roughness, over cut, circularity, and cylindricality, are measured. By considering each possible response as a separate target, Mo-Jaya (multi objective) may be used to optimize a wide range of performance indicators. The results of the multi-objective optimization problem are presented in the form of a set of Pareto optimum strategies. Three-dimensional (3D) graphics show how each response changes along the Pareto front. The optimal solutions for each combination of replies are selected from the whole solution. The outcome of a global optimization that factored in all five replies is also shown.

Multi-response optimization of EDM drilling parameters of the Nitinol SMA

The demand for Nitinol (SMA) is increasing rapidly for various applications. With the aim of optimum control parameters of EDM, 46 experiments completed on six specimens of 6.156 mm thickness using Sparkonix EDM drill machine. Current (I), voltage (V), charging-time (TON), discharging-time (TOFF), and dielectric pressure (DP) were taken as input control parameters. Single-indexed optimization of material removal rate (MRR), tool-wear rate (TWR), and degree of tapperness (DoT) are evaluated using gray relational grade (GRG). Individual control-parameter contributions are evaluated using Taguchi and ANOVA. The obtained optimal input control parameters were used for the confirmation experiment, and the obtained result gives good agreement to it. V and TON are found as the most significant parameters. Maximum and minimum values of MRR, TWR, and DoT have been recorded as 0.0277 & 0.0074 g/min, 0.0177 & 0.0033 g/min, and 0.032 & 0.01 radians respectively. MRR, TWR, and DoT improved by 49.1, 4.5, and 43.3 %, respectively.

Modelling and experimental investigation of process parameters in EDM of Si3N4-TiN composites using GRA-RSM

Electric discharge machining (EDM) is a highly promising machining process of ceramics. This research is an out of the paradigm investigation of EDM on Si3N4-TiN with Copper electrode. Ceramics are used for extrusion dies and bearing balls and they are more efficient, effective and even have longer life than conventional metal alloys. Owing to high hardness of ceramic composites, they are almost impossible to be machined by conventional machining as it entirely depends on relative hardness of tool with work piece. Whereas EDM offers easy machinability combined with exceptional surface finish. Input parameters of paramount significance such as current (I), pulse on (Pon) and off time (Poff), Dielectric pressure (DP) and gap voltage (SV) are studied using L25 orthogonal array. With help of mean effective plots the relationship of output parameters like Material removal rate (MRR), Tool wear rate (TWR), Surface roughness (Ra), Radial overcut (ROC), Taper angle (α), Circularity (CIR), Cylindricity (CYL) and Perpendicularity (PER) with the considered input parameters and their individual influence were investigated. The significant machining parameters were obtained by Analysis of variance (ANOVA) based on Grey relational analysis (GRA) and value of regression coefficient was determined for each model. The results were further evaluated by using confirmatory experiment which illustrated that spark eroding process could effectively be improved.

Optimization of EDM process parameters in machining Si3N4–TiN conductive ceramic composites to improve form and orientation tolerances

Abstract In this research, investigational and experimental work was carried out on the electric discharge machining (EDM) of a Si 3 N 4 –TiN ceramic composite using a copper electrode as the EDM tool. These composites are used in high-temperature environments, such as in metal forming, extrusion dies, turbine blade and non-ferrous molten metal handling components. The Si 3 N 4 –TiN composite is difficult to machine using conventional machining techniques. However, it can be easily machined using a spark EDM process to obtain accurate dimensional and geometric tolerances. The machining parameters, such as the current ( I ), pulse on time ( T on ), pulse off time ( T off ), dielectric pressure (DP) and spark gap voltage (SV), were investigated using a Taguchi L 25 orthogonal array. The output characteristics, such as the material removal rate (MRR), tool wear rate (TWR), wear ratio (WR), surface roughness (Ra), top radial over cut (ROC Top ), bottom radial over cut (ROC Bottom ), taper angle ( θ ), circularity (CIR), cylindricity (CYL), perpendicularity (PER) and run out (RO), were examined during the sparking operation. The significance of the machining parameters was obtained using analysis of variance (ANOVA) based on grey relational analysis (GRA), which showed that the current, pulse on time and spark gap voltage were the most significant parameters. The results were further confirmed using an experiment that illustrated that the spark eroding process could effectively be improved.

Optimization of Process Parameters to Improve Form and Orientation Tolerances in EDM of MoSi2-SiC Composites

In this research, an investigation and experimental work were carried out on electric discharge machining (EDM) of intermetallic base MoSi2-SiC ceramic composite with copper electrode. It is extremely difficult to machine MoSi2-SiC composite using conventional machining techniques. However, it can be easily machined by executing spark EDM parameters to induce the correct optimum result. These composites find their application in high-temperature environments, viz. fuel turbo pump rotors, inlet nozzles, combustion chambers, injectors, nozzle throats, and nozzle extensions. The sparking parameters, namely current (I), pulse on time (Ton), pulse off time (Toff), spark gap (SG), and dielectric pressure (DP), were investigated by L18 orthogonal array. The optimal process parameters were determined by the grey relational grade (GRG) obtained through the grey relational analysis (GRA) for multiple performance characteristics, viz. material removal rate (MRR), electrode wear rate (EWR), circularity (CIR), cylindricity (CYL), and perpendicularity (PER). The significant process parameters were obtained by analysis of variance (ANOVA) based on GRG, which showed current, pulse on time, and DP. The results were finally established using a confirmatory experiment, which showed the spark eroding process could effectively be improved.