Makine Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/263
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Article Citation - WoS: 7Citation - Scopus: 7Development and Experimental Investigation of Electrochemical Drilling Method Using Rotary Tube Tool(Gazi Univ, Fac Engineering Architecture, 2013) Ozerkan, H. Bekir; Çoğun, Can; Cogun, Can; Mekatronik MühendisliğiIn 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.Article Citation - WoS: 18Citation - Scopus: 19Effects of Electrolytic Copper and Copper Alloy Electrodes on Machining Performance in Electrical Discharge Machining (Edm)(Taylor & Francis inc, 2022) Esen, Ziya; Simsek, Ulke; Cogun, CanThe most important cost element of electric discharge machining (EDM) is the production of tool electrode (shortly electrode). In the EDM process, copper and its alloys are often used as electrode materials. The machining with EDM without increasing the costs can be achieved by selecting the proper electrode with low production and material costs as well as high workpiece material removal rate (MRR), low electrode wear rate (EWR), and relative wear (RW = MRR/EWR). In this study, the EDM performance outputs, namely, MRR and RW were experimentally investigated for electrolytic copper, CuCr1Zr (with and without aging treatment) and CuCo2Be alloy electrode materials for varying machining parameters. The performance outputs were affected by the electrode material and the applied aging treatment. The aged CuCr1Zr alloy electrodes had higher electrical conductivity and better machining performance than the as-received alloy. The CuCo2Be alloy electrodes exhibited moderate to high MRR; however, their RW was the highest. Although the electrolytic copper has moderate MRR performance compared to the investigated alloys, its low cost increased its performance index, making it a more suitable electrode material for EDM applications.Article Citation - WoS: 36Citation - Scopus: 42Improvement of Electric Discharge Machining (Edm) Performance of Ti-6al Alloy With Added Graphite Powder To Dielectric(Assoc Mechanical Engineers Technicians Slovenia, 2015) Cogun, Can; Unses, EmreTi-6Al-4V is a well-known Ti alloy widely used in the aerospace industry and belongs to the group of difficult-to-machine materials. It is less suitable for both conventional chip removal (machining) techniques and electric discharge machining (EDM). The very low material removal rate (MRR) of the Ti alloys during the EDM process causes prohibitively long machining durations. The goal of this study was to improve the EDM performance of the Ti-6Al-4V alloy by the addition of graphite powder into the kerosene dielectric liquid. The EDM performance was quantified by MRR, tool electrode wear rate (EWR), relative wear (RW), surface roughness and texture properties. The experiments conducted have shown that the use of graphite powder mixed with the kerosene dielectric (GPMKD) during machining considerably increases the MRR, improves the R-a and R-z(DIN) surface roughness and decreases the RW. 3D topographic views of the machined workpiece surfaces attained with GPMKD revealed uniformly distributed surface valleys and peaks over the surface and peaks with short arid round tops since the discharge energy of a spark is distributed over a large area at the machining gap. The experimental results strongly indicate the adaptability of the proposed technique to EDM die sinking and EDM drilling applications of the Ti-6Al-4V alloy in the aerospace industry. The ED machining performance of Ti-6Al-4V alloy using GPMKD is also compared to that of AISI 1040 steel, which is commonly used in EDM applications.Article Citation - WoS: 30Citation - Scopus: 34Performance and Surface Alloying Characteristics of Cu-Cr and Cu-Mo Powder Metal Tool Electrodes in Electrical Discharge Machining(Taylor & Francis inc, 2016) Uslan, Ibrahim; Usta, Yusuf; Cogun, Can; Gulcan, OrhanThe main objective of this study is to investigate the effect of Cu-Cr and Cu-Mo powder metal (PM) tool electrodes on electrical discharge machining (EDM) performance outputs. The EDM performance measures used in the study are material removal rate (MRR), tool electrode wear rate (EWR), average workpiece surface roughness (R-a), machined workpiece surface hardness, abrasive wear resistance, corrosion resistance, and workpiece alloyed layer depth and composition. The EDM performance of Cu-Cr and Cu-Mo PM electrodes produced at three different mixing ratios (15, 25, and 35wt% Cr or Mo), compacting pressures (P-c = 600, 700, and 800MPa), and sintering temperatures (T-s = 800, 850, and 900 degrees C) are compared with those machined with electrolytic Cu and Cu PM electrodes when machining SAE 1040 steel workpiece. Analyses revealed that tool materials were deposited as a layer over the work surface yielding high surface hardness, strong abrasion, and corrosion resistance. Moreover, the mixing ratio, P-c, and T-s affect the MRR, EWR, and R-a values.