No abstract

The Electric Discharge (EDM) method is a novel thermoelectric manufacturing technique in which materials are removed by a controlled spark erosion process between two electrodes immersed in a dielectric medium. Because of the difficulties of EDM, determining the optimum cutting parameters to improve cutting performance is extremely tough. As a result, optimizing operating parameters is a critical processing step, particularly for non-traditional machining process like EDM. Adequate selection of processing parameters for the EDM process does not provide ideal conditions, due to the unpredictable processing time required for a given function. Models of Multiple Regression and Genetic Algorithm are considered as effective methods for determining the optimal processing variables of Electrical Discharge Machining. The material removal rate (MRR) and tool wear (Tw) were investigated using the process variables of pulse on time (Ton), pulse off time (Toff), and current intensity (Ip). The established empirical models were used to perform Genetic Algorithm (GA) to maximize (MRR) and minimize (Tw). The optimization results were utilized to establish machining conditions, validate empirical models, and obtain optimization outcomes. The optimal result that appears in this work was the pulse on (176.261 μs), pulse off (39.42 μs), and current intensity (23.62 Amp.) to maximize the MRR to (0.78391 g/min) and reduce tool wear to (0.0451 g/min).

Monel 400 with low alloy steel dissimilar joints are widely used in oil industry, petrochemical and nuclear engineering, this kind of applications needs welding joints with good mechanical properties, stable magnetic permeability and good weldability. Difference in mechanical, chemical and physical properties between these unique alloys makes such joint difficult and joints mechanical properties and microstructure will be different from parent metals. In this study, GTAW process has been employed with ERNiCrFe-3 electrode to produce dissimilar welding joints with specifies welding procedure parameters, SEM/EDS microstructure analysis, microstructure optical test, Vickers microhardness and tensile test used to study microstructure details and its impacts on welding joint mechanical properties. Research results according to welding zone microstructure analyses shown formation of Widmanstatten ferrite structures and second phase particles with fine graine structure in low alloy steel side the formation of transion zone (TZ). Moreover, clearly fusion line (FL) clearly marked in Monel 400 side while weld metal solidification microstructure with (MGBs) and (SGBs) respectively and interdendritic microstructure observed in weld zone center. Weldment mechanical and microstructure examination indicated the ability to produce like this dissimilar joint with requirement of design criteria and indicated that the failure in like this joint excepted to be in low alloy steel side. The result and microstructure analyses of this research is very important to understanding the variation in welding zone and HAZ microstructure and its impact in weldment mechanical properties and establish the base to produced best welding procedure according to welding zone microstructure properties.

Electrical Discharge Machining (EDM) applies the concept of material eradication by utilizing electric spark erosion. The target of this exploration concentrates to examine the ideal procedure parameters of EDM on Aluminum 6061-T6as a workpiece with copper as a tool electrode. The effect of various process operators 'on machining rendering was examined. Internal factors with current (10, 20, 30) Ampere,  pulse on time (50, 100, 150) µs was used after which takes pulse off time (25, 50, 75) µs. All parameters applied for empirical acts with influence on Ra (surface roughness ).  The result showed that MRR" Material Removal Rate” is increment by expanding in current and pulse on time and it declines by expanding in pulse off time. Optimal condition are gained when using " Using current 30 Ampere, pulse on time is 150 µs and minimize assessment of pulse off time is 25 µs.

The objective of this work is the investigation of milling process variables which resulting in optimal values of the surface roughness and material removal rate during machining of 7024 Al-alloy. The machining operation implemented on C-TEK CNC milling machine. The effects of the selected parameters on the chosen characteristics have been accomplished using Taguchi’s parameter design approach; also ANOVA had been used to evaluate the contribution of each parameter on the process outputs. Different feed rates are used ranging from (60, 80 and 100) mm/min, found that high feed rates gives a high material removal rates and good surface roughness. On the other hand, using three levels of spindle speeds found that a higher spindle speeds gives better surface roughness with a little effect on MRR. The process results showed that maximum MRR achieved (2.40) mm3/min when machining feed rate (100) mm/min, spindle speed (1000) r.p.m, and depth of cut (0.6) mm while good surface roughness (0.41 µm) when machining feed rate (100) mm/min, spindle speed (1000) r.p.m, and depth of cut (0.2) mm. The level of importance of the machining parameters for material removal rate and surface roughness and is determined by using Taguchi designing experiments and the variance analysis (ANOVA).