Endüstri Mühendisliği Bölümü Koleksiyonu
Bu koleksiyon için kalıcı URI
Güncel Gönderiler
Öğe Study on delamination factor and surface roughness in abrasive water jet drilling of carbon fiber-reinforced polymer composites with different fiber orientation angles(Springer Science and Business Media Deutschland GmbH, 2021) Altın Karataş, Meltem; Motorcu, Ali Rıza; Gökkaya, HasanCarbon fiber-reinforced polymer (CFRP) composites are used in aerospace applications because of their superior mechanical properties and light weight. Avoiding damage in the machining of CFRP composites is difficult using traditional methods. Abrasive water jet (AWJ) has recently become one of the preferred machining methods for CFRP composites. This study evaluated the AWJ machinability of CFRP composites having three different fiber orientation angles (M1: [0°/90°]s, M2: [+ 45°/− 45°]s, and M3: [0°/45°/90°/− 45°]s) according to the delamination factor (Df), and the average surface roughness (Ra) as quality characteristics of the drilled holes. The aim of the study was to investigate the effects of different levels of AWJ drilling parameters on the delamination factor and surface roughness and to determine the optimum drilling parameter levels that provide minimum delamination formation and surface roughness values. For this purpose, AWJ drilling experiments were carried out using the Taguchi L16 (44) orthogonal array. Water pressure (WP), stand-off distance (L), traverse feed rate (F), and hole diameter (D) were chosen as process parameters. Analysis of variance was used to determine the percentage effects of the AWJ drilling process parameters. The microscopic surface roughness and delamination formation properties of the machined surfaces were revealed using a scanning electron microscope and an optical microscope, respectively. The most effective parameters on Df and Ra in the AWJ drilling of M1, M2 and M3 CFRP materials were determined to be water pressure, and stand-off distance. Minimum Df and Ra values were obtained when AWJ drilling the M3 CFRP composite with a fiber orientation angle of [0°/45°/90°/− 45°]s. Minimum delamination formation and very good surface quality can be obtained when the optimum process parameters determined in this study are used in the planning process for the AWJ drilling of CFRP composites having different fiber orientation angles.Öğe Multi-Objective Optimization of Process Parameters for Drilling Fiber- Metal Laminate Using a Hybrid GRA-PCA Approach(Belgrade University, 2021) Ekici, Ergün; Motorcu, Ali Rıza; Uzun, GültekinThis study investigated the effects of drilling parameters and cutting tool coating conditions on the thrust force, surface roughness, and delamination factor in the drilling of fiber-reinforced carbon reinforced aluminum laminate (CARALL) composite, a commercial type of fibermetal laminate. Gray relational analysis (GRA) was used as a multiobjective optimization method to determine optimum processing parameters and principal component analysis (PCA) was used to determine the weights. According to the findings of this experimental study, the most effective control factors for the thrust force, surface roughnes, and delamination factor were the feed rate, tool coating conditioncutting speed interaction, and tool coating condition, with 93.87%, 66.504%, and 29.137% contribution rates, respectively. From the results of the GRA-PCA analysis, the optimum levels of the control factors were determined as 110 m/min cutting speed, 0.1 mm/rev feed rate, and the uncoated tool.Öğe An Experimental Study on Hole Quality and Different Delamination Approaches in the Drilling of CARALL, a New FML Composite(Belgrade University, 2021) Ekici, Ergün; Motorcu, Ali Rıza; Yıldırım, EnsarIn this study, the hole quality was investigated in the drilling of CARALL composite. In addition, the delamination factor calculation approaches of Chen, Davim, and Machado were compared in terms of the delamination damage at the hole entrance surface. Chen's approach is based on the conventional delamination factor (Fd) and Davim's on the adjusted delamination factor (Fda). Finally, Machado's approach is based on the minimum delamination factor (Fmin). The values closest to the nominal hole diameter value were obtained with the uncoated (T1), followed by the TiN-TiAlN-coated (T2) and TiAl/TiAlSiMoCr-coated (T3) carbide drills, respectively. The average circularity error values for the hole top and bottom surfaces were 6.184 µm, 7.647 µm, and 8.959 µm for T1, T2, and T3 tools, respectively. Delamination factor values varied between 1.174 and 1.804. The Fda values were found to be the highest, followed by Fd values, with Fdmin values determined as the lowestÖğe Evaluation of the effects of drilling parameters, tool geometry and core material thickness on thrust force and delamination in the drilling of sandwich composites(World Scientific Publishing, 2021) Ekici, Ergün; Uzun, Gültekin; Altaş, SedatThis study examined the effects of drilling parameters, tool geometry, and core material thickness (CMT) on thrust force and the delamination factor in the drilling of sandwich composites. Aluminum honeycomb (10 and 15mm in thickness) was used as the core material, with carbon fiber-reinforced polymer (CFRP) as the top and bottom surfaces. In the drilling experiments, three different cutting speeds (60, 78 and 100 m/min) and two different feed rates (0.05 and 0.075 mm/rev) were used. Drills having a diameter of 6.35 mm and three different geometries (candlestick drills, twist drills and dagger drills) were used in the experiments. At the end of the experiments, thrust force was seen to increase with increased feed rate and CMT. Increased cutting speed generally decreased the thrust forces and the minimum thrust force was achieved with the 10 mm thick core material, 0.05 mm/rev feed rate and 100m/min cutting speed using the dagger drill. The delamination factor at the entrance area was very low when drilling the sandwich composites and there was no significant difference based on drilling parameters, tool geometry, or CMT. Tool geometry was the main effective factor on exit delamination, and the highest delamination occurred with the use of the candlestick drill. Although increased feed rate increased delamination with all tools, with the dagger drill, increased cutting speed led to a severe increase. Delamination, tearing, and uncut fiber formation were observed when images of the exit areas of the drilled holes were examined.Öğe Performance of Multilayer Coated and Cryo-treated Uncoated Tools in Machining of AISI H13 Tool Steel—Part 2: HSS End Mills(Springer, 2021) Çiçek, Adem; Ekici, Ergün; Kıvak, Turgay; Kara, Fuat; Uçak, NecatiThis part of the study aimed to investigate the effects of cryogenic treatment applied to uncoated high speed steel (HSS) end mills on cutting forces (Fc), surface roughness (Ra), and tool life. The milling tests were performed at four cutting speeds (40, 50, 60, and 70 m/min), three feeds (0.018, 0.024, and 0.03 mm/rev), and a depth of cut (2 mm) under dry and wet conditions. Three categories of uncoated HSS end mills were used in the tests: conventional heat treated (CHT), cryo-treated (CT), cryo-treated and tempered uncoated (CTT), and TiAlN/TiN multilayer coated (MLC) end mills. The test results showed that the lowest values of Fc and Ra were measured with the use of MLC end mills. However, the cryogenic treatment provided in a reduction in Fc and Ra values. In addition, under wet conditions, the CTT end mills exhibited better performance than the CHT ones by 71.4%. The test results showed while cryogenic treatment is a useful and cheap application in steels, it does not have the ability to compete with coating technology in terms of tool life in milling of hot work tool steel. This paper is organized into two sections. In the first section, cutting performance of cryo-treated and multilayer coated end mills is evaluated. In the second section, performance comparison of cryo-treated WC-Co (Part 1), HSS (Part 2), and MLC end mills in milling of AISI H13 hot work tool steel is presented.Öğe Performance of Multilayer Coated and Cryo-Treated Uncoated Tools in Machining of AISI H13 Tool Steel—Part 1: Tungsten Carbide End Mills(Springer, 2021) Çiçek, Adem; Kıvak, Turgay; Ekici, Ergün; Kara, Fuat; Uçak, NecatiThis paper focused on the performance of tungsten carbide end mills in machining of AISI H13 hot work tool steel under dry and wet conditions. The tool performance was evaluated in terms of resultant cutting force (Fc), average surface roughness (Ra) and tool life. In the milling tests, four categories of end mills were used: untreated (U), cryo-treated (CT), cryo-treated and tempered uncoated (CTT) and TiAlN/TiN multilayer coated (MLC). The tests were performed at four cutting speeds (80, 100, 120, 140 m/min), three feeds (0.08, 0.12, 0.16 mm/rev) and a depth of cut (2 mm). The test results showed that the lowest values of Fc and Ra were obtained with the use of MLC end mills. However, the cryogenic treatment was also effective on decreasing Fc and Ra. In addition, while the CTT end mills provided a slight improvement in tool life under dry conditions, they showed a remarkable improvement of 126.1% in comparison with the untreated ones under wet conditions. Although the CTT end mills exhibited a superior performance to U and CT ones, the MLC end mills were much more resistant to abrasive wear. This study is organized into two parts (WC-Co and HSS) to observe the effects of deep cryogenic treatment on performance of two different tool materials and to compare cryo-treated end mills with multilayer coated ones. This part is related to the cryogenic treatment of tungsten carbide end mills, whereas part two is regarding cryo-treated HSS end mills.
