Yazar "Ciftci, Ibrahim" seçeneğine göre listele
Listeleniyor 1 - 10 / 10
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe APPLICATION OF THE TAGUCHI METHOD TO OPTIMIZE THE CUTTING CONDITIONS IN HARD TURNING OF A RING BORE(Inst Za Kovinske Materiale I In Tehnologie, 2015) Boy, Mehmet; Ciftci, Ibrahim; Gunay, Mustafa; Ozhan, FeridunThis paper is focused on optimizing the cutting conditions for the surface roughness, inner-diameter error and roundness obtained in hard turning of an inner ring bore. The hard-turning experiments were conducted on hardened and tempered AISI 52100 bearing rings using the L9 orthogonal array on a CNC lathe. The cutting speed, feed rate and number of the machined part were selected as control factors. The optimum cutting conditions were determined using the signal-to-noise (SIN) ratio. S/N ratios were calculated using the lower-the-better approach. An analysis of variance (ANOVA) was also employed to determine the level of the effect of the control factors for the surface roughness, inner-diameter error and roundness. The statistical analysis showed that the feed rate was the most significant factor for the surface roughness while the cutting speed was the most significant factor for the roundness and inner-diameter error. Finally, the optimum cutting conditions were further confirmed with confirmation tests.Öğe Cutting parameter optimization in shoulder milling of commercially pure molybdenum(Springer Heidelberg, 2018) Gokce, Huseyin; Ciftci, Ibrahim; Demir, HalilDue to its superior properties such as high melting point (2617 degrees C), high thermal conductivity and low thermal expansion at higher temperatures, molybdenum is a refractory metal and is used for making critical parts in defense, space, electronics and nuclear industries. High cost of molybdenum makes the selection of suitable cutting conditions imperative in machining operations in order to obtain the required surface quality and dimensional accuracy. In this study, suitable cutting tools and cutting parameters were aimed to be determined in terms of cutting forces (F-c) and average surface roughness (R-a) when shoulder milling commercially pure molybdenum. The milling tests were carried out at 0.05, 0.1, 0.15, 0.2 mm/tooth feed rates and 75, 100, 125, 150 m/min cutting speeds using four different cutting tools. The Taguchi's experimental design (L16 orthogonal array) technique was implemented. Analysis of variance was used to determine the effects of cutting tools and cutting parameters on R-a and F-c. The results showed that the feed rate is the most influential parameter for F-c while the cutting speed is for R-a.Öğe The Effect of Aging and Sliding Speed on Wear Behaviour of Cu-Cr-Zr Alloy(Carl Hanser Verlag, 2013) Ozyurek, Dursun; Ciftci, Ibrahim; Tuncay, TanselIn this study, the sliding wear behaviour of non-aged and aged Cu-Cr-Zr alloy specimens were investigated. The specimens were aged for 2 h at the temperatures of 450 degrees C and 475 degrees C. Prior to the wear tests, microstructural examinations and hardness measurements were performed on all Cu-Cr-Zr alloy specimens. The wear tests were performed on a pin-on disk type wear apparatus at the sliding speeds of 0.5 ms(-1), 1.0 ms(-1) and 1.5 ms(-1) as well as under 40 N applied load. After the wear tests, the worn surfaces of all samples were analyzed by SEM and energy dispersive X-ray spectroscopy (EDS). The experimental results indicated that aging heat treatment led to increase in the hardness values of Cu-Cr-Zr alloys and the highest wear loss was observed for non-aged specimens. With increasing sliding speed, the wear loss increased to a maximum value beyond which it decreased.Öğe Experimental investigation and prediction of wear properties of Al/SiC metal matrix composites produced by thixomoulding method using Artificial Neural Networks(Elsevier Sci Ltd, 2014) Ozyurek, Dursun; Kalyon, Ali; Yildirim, Musa; Tuncay, Tansel; Ciftci, IbrahimIn this study, the wear properties of the SiC particle reinforced aluminium (A356) composite materials (MMCs), produced with thixomoulding method, were investigated both by experimental and Artificial Neural Network (ANN) model in order to determine the weight loss after the wear tests. Two different temperatures (590 degrees C and 600 degrees C) were used in production of the MMCs containing 5%, 10%, 15% and 20% SiC (vol%). The samples of MMC were tested at 2 ms (1) constant sliding speed under 30 N and 60 N loads against four different sliding distances (500 m, 1000 m, 1500 m, and 2000 m). The results indicated that by increasing the production temperature increased the grain size of the MMCs was increased, but the hardness was decreased. The MMCs produced at 590 degrees C were found to have lower weight loss as compared with ones produced at 600 degrees C. In the theoretical prediction model of the MMCs, weight loss, SiC per cent, production temperature, applied weight and sliding distance were used as input values. After comparing the experimental results and the ANNs predicted data it was observed that R-2 was 0.9855. This shows that the developed prediction model has a high level of reliability. (C) 2014 Elsevier Ltd. All rights reserved.Öğe The Influence of Chip Breaker Geometry on Tool Stresses in Turning(Assoc Mechanical Engineers Technicians Slovenia, 2011) Gurbuz, Huseyin; Kurt, Abdullah; Ciftci, Ibrahim; Seker, UlviIn this study, the influence of different chip breaker geometries on cutting forces and tool stresses developed during turning was investigated experimentally. For this purpose, turning tests in accordance with ISO 3685 were carried out on AISI 1050 steel using uncoated and coated cemented carbide cutting tools with different chip breaker geometries. The tests were carried out at different cutting parameters. The cutting forces were measured using a Kistler 9257B type dynamometer The effect of cutting force variation on tool stresses was analysed using finite element analysis software (ANSYS). The analyses results showed that the coated tools were subjected to higher stresses than the uncoated ones. However the stresses on the uncoated tools were found to be higher than those on the coated tools at the heavy cutting conditions. In addition, the chip breaker geometry was also found to result in variation in the stresses acting on the tools. (C)2011 Journal of Mechanical Engineering. All rights reserved.Öğe An Investigation into the Influences of Grain Size and Grinding Parameters on Surface Roughness and Grinding Forces when Grinding(Assoc Mechanical Engineers Technicians Slovenia, 2010) Demir, Halil; Gullu, Abdulkadir; Ciftci, Ibrahim; Seker, UlviThis study was carried out to investigate the effects of grain size on workpiece surface roughness and grinding forces when surface grinding AISI 1050 steel. A previously designed and constructed dynamometer was used to measure and record the forces developed during grinding. Grinding tests were carried out using different grinding wheels of different grains. Ground still ace roughness measurements were also carried out. The results showed that grain size significantly affected the grinding forces and surface roughness values. Increasing grain size and depth of cut increased the grinding forces and surface roughness values. For different grain sizes, depth of cuts of 0.01 and 0.02 mm did not result in any significant variations in the grinding forces but further increase in depth of cut led to variations of up to 50% in grinding forces. (C) 2010 Journal of Mechanical Engineering. All rights reserved.Öğe An investigation into the wear behaviour of TiB2 particle reinforced aluminium composites produced by mechanical alloying(Walter De Gruyter Gmbh, 2011) Ozyurek, Dursun; Ciftci, IbrahimIn this study, wear behaviour of TiB2 particle reinforced aluminium (Al) composites produced by the mechanical alloying method was investigated. TiB2 ceramic particles of four different volume fractions were mechanically alloyed with Al and A356 alloy matrix materials. The mechanically alloyed particles were cold presses and then sintered at 550 degrees C. After the sintering process, the composites were characterised through hardness measurements, scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Wear tests were also carried out on a pin-on-disc type wear apparatus under 10, 25 and 50 N loads. Wear loss of the composites were found to decrease with increasing hardness which increased with increasing TiB2 particle volume fraction. However, increasing the applied load and sliding distance increased the wear loss. Wear surface examinations showed that various wear mechanisms were effective in wear of the composites.Öğe Investigation on The Effects of Mechanical Features of AISI 5140 Steel on Tool Wear and Cutting Forces(Gazi Univ, 2012) Uzun, Gultekin; Ciftci, IbrahimIn this study, machining tests have been performed by means of machining method so that effects of changes in microstructure and mechanic features of hot rolled aisi 5140 steel of which microstructures and mechanic features were changed by heat treatment on tool wearing and cutting forces will be examined. The tests were carried out with four different cutting speeds (90-110-130-150 m/min.), development of 0.1mm/rev and cutting depth of 1mm under dry cutting conditions. During tests, it has generally been observed that cutting forces are obviously decreased while cutting speeds are increasing. The highest cutting force (593.78 N) has been obtained in the result of processing the sample which was hardened in oil having 755 degrees C temperature was machined in cutting speed of 90 m/min. It has been thought that max. hardness and strength of this sample resulted in highest cutting force. It has been observed that apparent tool wearing occurred in materials of which hardness is relatively high.Öğe Optimization of Surface Roughness in Turning Mg2Si Particle Reinforced Magnesium(Gazi Univ, 2018) Akgun, Mahir; Demir, Halil; Ciftci, IbrahimIn this study, Mg2Si reinforced Mg alloy material was produced by adding 10 % Al12Si alloy ingot to Mg matrix by conventional casting method and then the melt was poured into a metal mould in cylindrical form. Machining tests were carried out on these cast alloys through single point turning method. Optimum machining conditions was aimed to be determined by investigating the effects of cutting parameters on surface roughness. For this purpose, the machining tests were performed without coolant on a CNC turning centre at four different cutting speeds (250, 350, 450 and 550 m/min), two different feed rates (0.1 and 0.2 mm/rev) and two different tool tip radii (0.4 mm ve 0.8 mm). The experimental design was conducted according to Taguchi's L8 orthogonal array. Machining experiments were carried out on CNC lathe under dry cutting conditions. ANOVA was used to determine the effect of cutting parameters on the surface roughness. According to the obtained analysis results, it was seen that the most influential parameters on surface roughness was feed rate by 57.6 %.Öğe The tribological properties of A356-SiCp metal-matrix composites fabricated by thixomoulding technique(Walter De Gruyter & Co, 2012) Ozyurek, Dursun; Yildirim, Musa; Ciftci, IbrahimIn this study, A356-SiCp metal-matrix composites were produced through thixomoulding process, and these composites were subjected to wear tests. The composites containing various volume fractions of SiCp particles (5%, 10%, 15% and 20%) as the reinforcement were produced at two different temperatures of 590 degrees C and 600 degrees C. The influences of processing temperatures and reinforcement ratio on the properties and wear behaviour of the composites were investigated. Prior to the wear tests, microstructural properties and hardness of the composites were determined. For the wear tests, a pin-on-disc-type wear apparatus was employed to carry out the wear tests. The wear tests were carried out at 2.0 m/s sliding speed under 15 N load and for four different sliding distances. A scanning electron microscope (SEM) was used to examine the wear mechanisms on the worn surfaces of the composites. The results indicated that sphericity rate and hardness of the composites produced at 590 degrees C were higher than those of the composites produced at 600 degrees C. In addition, the composites produced at 590 degrees C exhibited lower weight loss and friction coefficient.
