Browsing by Author "Ozerkan, H. Bekir"

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Citation - WoS: 7
Citation - Scopus: 7
Development and experimental investigation of electrochemical drilling method using rotary tube tool
(Gazi Univ, Fac Engineering Architecture, 2013) Ozerkan, H. Bekir; Cogun, Can; 132262; 3837; Mekatronik Mühendisliği
In this study, a new hybrid electrochemical drilling (ECD) method, based on electrochemical machining in nonconventional machining processes, was developed. In the developed method, tube tool makes rotary motion together with inner through hole flushing. A small scale prototype ECD machine has been designed and manufactured to test the developed method. One of the important features of the new system is the regulation of tool feed rate using current feedback control. The Hadfield (manganese) steel, whose strain hardening behavior makes it very difficult to machine with conventional methods, and AISI 1040 steel, whose machinability is fairly good, were drilled using the prototype machine and results were compared. Workpiece material removal rate increased with the increasing machining voltage, tool rotational speed, electrolyte concentration and flushing pressure in both types of steels. Average radial overcut values increased with the rotational speed of the tool. The AISI 1040 steel hole geometries were regular than that of Hadfield steel. Experimental results showed that deep holes can be drilled successfully with the proposed hybrid ECD method.
Citation - WoS: 10
Citation - Scopus: 9
The effect of powder mixed and heated dielectric on drilling performance of electric discharge machining (EDM)
(Gazi Univ, Fac Engineering Architecture, 2016) Erdem, Oguz; Cogun, Can; Urtekin, Levent; Ozerkan, H. Bekir; Uslan, Ibrahim; 3837; Mekatronik Mühendisliği
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.