Md. Ashikur Rahman Khan

Optimization of Machining Parameters on Tool Wear Rate of Ti-6Al-4V through EDM using Copper Tungsten Electrode A Statistical Approach

Electrical discharge machining (EDM) is relatively modern machining process having distinct advantages over other machining processes and able to machine Ti-alloys effectively. This paper attempts to investigate the effects of peak ampere, pulse on time and pulse off time on tool wear rate (TWR) of titanium alloy Ti-6Al-4V in EDM utilizing copper tungsten as an electrode and positive polarity of the electrode. A mathematical model for electrode wear rate is developed in this paper. Design of experiments method and response surface methodology techniques are implemented. The validity test of the fit and adequacy of the proposed models has been carried out through analysis of variance. It can be seen that as the peak current increases the TWR decreases till certain ampere and then increases. The excellent surface finish is investigated in this study at short pulse on time and in contrast the long pulse duration causes the lowest TWR. Long pulse off time provides minimum TWR and the impact of pulse interval on TWR depends on peak current. The result leads to wear rate of electrode and economical industrial machining by optimizing the input parameters.

Optimization of Machining Parameters on Surface Roughness in EDM of Ti-6Al-4V Using Response Surface Method

This paper presents the influence of EDM parameters in terms of peak ampere, pulse on time and pulse off time on surface roughness of titanium alloy (Ti-6Al-4V). A mathematical model for surface finish is developed using response surface method (RSM) and optimum machining setting in favor of surface finish are evaluated. Design of experiments (DOE) techniques is implemented. Analysis of variance (ANOVA) has been performed to verify the fit and adequacy of the developed mathematical models. The acquired results yield that the increasing pulse on time causes fine surface till a certain value and then deteriorates the surface finish. It is investigated that about 200 µs pulse off time produce superior surface finish. These results lead to desirable surface roughness and economical industrial machining by optimizing the input parameters.

Current Research Trends on Dry, Near-Dry and Powder Mixed Electrical Discharge Machining

Electrical discharge machining (EDM) technique has been widely used in modern metal working industry for producing complex cavities in dies and moulds, which are otherwise difficult to create by conventional machining. The process has the advantage of being able to machine hardened tool steels. However, its low machining efficiency and poor surface finish restricted its further applications. To address these problems, one relatively new technique used to improve the efficiency and surface finish is EDM in the presence of powder suspended in the dielectric fluid. Powder mixed electric discharge machining (PMEDM) is one of the recent innovations for the enhancement of capabilities of EDM process. In PMEDM, the electrically conductive powder is mixed in the dielectric fluid of EDM, which reduces the insulating strength of the dielectric fluid and increases the spark gap between the tool and workpiece. As a result, the process becomes more stable, thereby, improving the material removal rate (MRR) and surface finish. Moreover, the surface develops high resistance to corrosion and abrasion. This paper presents the current research trends on dry, near dry EDM and review on research carried out in the area of PMEDM.