Browsing by Author "Ürtekin, Levent"

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Citation Count: Ürtekin, Levent...et al. (2021). "Experimental Investigation on Wire Electric Discharge Machining of Biodegradable AZ91 Mg Alloy", Journal of Materials Engineering and Performance, Vol. 30, No. 10, pp. 7752-7761.
Experimental Investigation on Wire Electric Discharge Machining of Biodegradable AZ91 Mg Alloy
(2021) Ürtekin, Levent; Özerkan, Hacı Bekir; Çoğun, Can; Genç, Asım; Esen, Ziya; Bozkurt, Fatih; 3837; 52373
The AZ91 magnesium alloy, used commonly as a biodegradable material in biomedical applications, is generally formed by conventional casting method (CCM) and high-pressure die casting method (HPDCM). The AZ91 alloys exhibit poor machinability with conventional chip removal methods since they degrade at elevated temperatures. In this study, the wire electric discharge machining (WEDM) was presented as a candidate process to machine the AZ91 alloy since no cutting stresses and plastic deformations were applied by the cutting tool to the part causing elevated temperatures. In this context, the WEDM machinability of the AZ91 alloy samples produced by cold chamber HPDCM and CCM at different process parameters, was experimentally investigated. The machining performance outputs (the machining current (I), the machining rate (MR), the average surface roughness (Ra), and surface topography) were found for the varying process parameters [pulse time (ts), pulse-off time (toff), dielectric flushing pressure (Pd), and wire speed (Vw)]. The present study revealed that the I and the MR were significantly dependent on the density, the porosity, and the micro structure of the samples, and the HPDCM samples gave the higher MR and the smoother surface than that of the CCM. © 2021, ASM International.
Citation Count: Erdem, Oguz...et al. (2016). "The effect of powder mixed and heated dielectric on drilling performance of electric discharge machining (EDM)", Journal of the Faculty of Engineering and Architecture of Gazi University, Vol. 31, No. 3, pp. 531-544.
The effect of powder mixed and heated dielectric on drilling performance of electric discharge machining (EDM)
(Gazi Univ, Fac Engineering Architecture, 2016) Erdem, Oğuz; Çoğun, Can; Ürtekin, Levent; Özerkan, H. Bekir; Uslan, İbrahim; 3837
In this study, heated silicon oil with added carbon and starch powders was used as dielectric liquid, instead of common hydro-carbon based dielectrics, to obtain better hole surface quality with rotating brass tube electrode in electric discharge machining (EDM). The electro-rheometer tests were conducted to find out the suitable temperature and powder concentration values of the electro-rheological (ER) dielectric under the electric field. Higher workpiece material removal rates (MRR) was obtained in carbon powder added dielectrics than the starch powder added ones for rotating and non-rotating electrodes. The optical microscope observations of the machined hole surfaces indicated that the carbon powder added dielectrics reduced the diameter and depth of the discharge craters, thereby resulting in uniformly distributed and round top peaked surface topography. The starch powder addition to the carbon mixed dielectric further improved the surface quality for both rotating and non-rotating electrodes cases at 30 degrees C and 75 degrees C dielectric temperatures.