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Study on Near-Dry EDM Performance Characteristics of MSGNP/Al-7075 Using Air, Argon, Nitrogen, and Freon Dielectric Medium

Abd Haneen Lateef, Ali Saad Mahmood

Advances in Science and Technology. Research Journal

2023

Vol. 17, no 6

254--273

The primary aim of the current study is to investigate the influence of input parameters of near dry electric discharge machine (ND-EDM) upon the output performances including the MRR, EWR, SR and WLT for the fabricated new metal matrix composite (MMCs) of aluminum A7075 matrix nanocomposites by adding 8% of Microscopic Slide Glass Nanoparticles (MSGNPs) as reinforcements to improve the metallurgical and mechanical properties of Al-7075/MSGNP composites using stir-casting method. In (ND-EDM), the dielectric medium plays a significant role in the procedure responses. In the current work, the vegetable oil with gases, such as air, Ar, mix (Ar+N2), and Freon were used as a dielectric media. The obtained results show that the highest MRR achieved when using the vegetable oil + Freon gas, reached 29.425 mm3/min, and then 26.943 mm3/min when using the vegetable oil + Air as a dielectric. The lowest EWR achieved when employing the vegetable oil + Argon gas, reached 0.120 mm3/min, and then 0.175 mm3/min. The lowest SR values obtained for all the designed experiments reached 3.287 µm when using Ip (10 A), Ton (1600 µsec), and Ar additive gas, followed by 4.567 µm when adding Freon gases to the dielectric. In the ND-EDM, the average of recast white layer thickness in the case of vegetable oil + air, vegetable oil + Ar, vegetable oil + mix (Ar-N2), and vegetable oil + Freon was 1.505, 1.180, 0.456, and 0 μm, respectively. These unique results can be used to increase the service and fatigue life of parts and machines that are exposed to sudden dynamic mechanical or thermal loads, without the need for additional operations to remove this brittle layer, which causes the failure of these parts with a short service life. The created mathematical models displayed a higher value of R-Square and the adjusted R-square, which manifest a better fit. Normal probability plots of the residuals for MRR, EWR, and SR elucidated an obvious pattern (i.e., the points were stabilized in a straight line) which indicates that every factor affects the mentioned responses and the outcomes of these responses from the regression model (predicted value by factorial) and the true values (from the experiments).

Influence of machining parameters on the surface integrity in electrical discharge machining

Boujelbene M., Bayraktar E., Tebni W., Ben Salem S.

Archives of Materials Science and Engineering

2009

Vol. 37, nr 2

110-116

Purpose: The aim of this research is to make a study of the influence of machining parameters on the surface integrity in electrical discharge machining. The material used for this study is the X200Cr15 and 50CrV4 steel for dies and moulds, dies castings, forging dies etc. Design/methodology/approach: The methodology consists of the analysis and determination of the white layer thickness WLT, the material removal rate MRR, the electrode wear ratio EWR and the micro hardness of each pulse discharge energy and parameters of electrical discharge machining. Findings: The Results of the tests undertaken in this study show that increasing energy discharge increase instability and therefore, the quality of the workpiece surface becomes rougher and the white layer thickness increases. This is due to more melting and recasting of material.With the increase of the discharge energy, the amount of particles in the gap becomes too large and can form electrically conducting paths between the tool electrode and the workpiece, causing unwanted discharges, which become electric arcs (arcing). these electric arcs damage the electrodes surfaces (tool and workpiece surfaces) and can occur microcracks. Research limitations/implications: A possible future work would be the development of a general the phenomenal of the residual stress of the wire electrical discharge machining in titanium alloys. The behavior is of the residual stress studies are planed in the future. Practical implications: The relationship found between the total energy of discharge pulses, composition of the steels and the type of machining on the surface integrity (the surface texture, the metallurgical surface aspect, the microhardness in the heat affected zone, HAZ) of different workpiece materials has an important practical implication since it allows selecting the best cutting condition combination from the points of view both the security and the economy for the established requirements in each case. Results are of great importance for aerospace and automotive industry. Originality/value: The paper is original since the bibliographical review has allowed testing that, although works about these themes exist, none approaches the problem like it has been made in this work. The paper could be an interesting source of information for engineers and researchers who work with machining dies and also significant complex parts in aeronautics.