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Öğe Investigation of plasma arc cutting parameters with type-2 fuzzy set and system(De Gruyter, 2013-10) Çelik, Yahya Hışman; Özek, Cebeli; Bulut Özek, MüzeyyenThe objective of the present study was it to design a type-2 fuzzy set and system in order to predict surface roughness and hardness depending on the parameters (material thickness, cutting speed, arc voltage and current) of the plasma arc cutting process of S235JR sheet materials. Therefore, some experimental studies were conducted. The experimentally determined data were used to describe the type-2 fuzzy set and system. Type-2 fuzzy set and system was found to be usefull to predict surface roughnes and hardness. According to the obtained values, the best surface roughness and the values closest to the hardness of the raw material were obtained at 1500 mm/min cutting speed, 8 mm material thickness, 115 V arc voltage and 80 A current.Öğe An experimental investigation on bushing geometrical properties and density in thermal frictional drilling(Multidisciplinary Digital Publishing Institute (MDPI), 2018-12-18) Demir, Zülküf; Özek, Cebeli; Bal, MuhammedIn thermal friction drilling (TFD) operations, the geometrical dimensions of bushing shape, height and wall thickness are the most vital consequences, since these increase the connecting length and strength. In this paper, AA7075-T651 aluminum alloys with 2, 4, 6, 8, and 10 mm thicknesses were drilled with the TFD process in order to investigate density, volume ratio, and height and wall thickness of the bushings. The experiments were conducted at constant spindle speed and feed rate conditions by using High Speed Steel (HSS) conical tools of 5, 10, 15, and 20 mm in diameter. It was experimentally found that the bushing height and the wall thickness had a tendency to increase linearly with the increase in both material thickness and tool diameter. The effect of tool diameter was found to have more influence on the measurable values than the thickness of the drilled material. The density of the bushing changed trivially. Approximately 70-75 percent of the evacuated material formed the bushing shape in TFD operations.Öğe Effect of cutting parameters on workpiece and tool properties during drilling of Ti-6Al-4V(De Gruyter, 2016-05-23) Çelik, Yahya Hışman; Yıldız, Hakan; Özek, CebeliThe main aim of machining is to provide the dimensional preciseness together with surface and geometric quality of the workpiece to be manufactured within the desired limits. Today, it is quite hard to drill widely utilized Ti-6Al-4 V alloys owing to their superior features. Therefore, in this study, the effects of temperature, chip formation, thrust forces, surface roughness, burr heights, hole diameter deviations and tool wears on the drilling of Ti-6Al-4 V were investigated under dry cutting conditions with different cutting speeds and feed rates by using tungsten carbide (WC) and high speed steel (HSS) drills. Moreover, the mathematical modeling of thrust force, surface roughness, burr height and tool wear were formed using Matlab. It was found that the feed rate, cutting speed and type of drill have a major effect on the thrust forces, surface roughness, burr heights, hole diameter deviations and tool wears. Optimum results in the Ti-6Al-4 V alloy drilling process were obtained using the WC drillÖğe A fuzzy logic model to determine the effects of die/blank holder angle and punch radius on drawing ratio in angular deep drawing dies(Journal of Intelligent & Fuzzy Systems, 2013-05) Çelik, Yahya Hışman; Özek, Cebeli; Bulut Özek, MüzeyyenDeep drawing process is one of the widely used methods in sheet-metal forming. With the deep drawing method, products of various geometrical shapes such as saucepans, tubes, perfume and soft drink cans can be obtained easily. Therefore, the optimization of the deep drawing process is very important for the industry. In conventional deep drawing method, no angle is given to the surfaces of die and pressure plate. Both die and pressure plate and the geometrical shape of die and punch have a significant effect on drawing ratio. In this study, the effect of angles and radii on the drawing ratio of blank holder and punch forces were theoretically calculated and experimentally investigated in order to deep drawing the DIN EN 10130-91 sheet by giving angles on the die/blank holder surfaces and radii on the punch edge surfaces. In addition, the data obtained from the experimental study were calculated with the Fuzzy Logic Model and the optimum and the lowest drawing ratios for the die and punch radius as well as the die/blank holder were determined. The optimum drawing ratio in the experimental study was obtained as β = 2.3, when the die and punch radius was R = 10 mm and the die/blank holder angle was θ = 12.5°, and as β = 2.2 in the Fuzzy Logic model. The lowest drawing ratio was obtained as β = 1.8 when the blank holder angle was θ = 0° in the experimental study and as β = 1.82 in the Fuzzy Logic model.
