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Öğe Effects of cutting parameters and point angle on thrust force and delamination in drilling of CFRP(De Gruyter, 2014-11-14) Çelik, Yahya Hışman; Kılıçkap, Erol; Yardımeden, AhmetParts made of composite materials are generally produced by near-net-shape technology. However, additional machining operations such as drilling are often required to facilitate components assembling. Drilling of composite materials is also a common process in the assembly of aerospace and automotive composite structures. During drilling, unlike the conventional materials, a few damage forms may take place. Among these damage forms, the delamination is the most important one. Therefore, the experimental studies carried out on drilling of CFRP composite materials for determining optimum processing parameters are of great importance. In this particular study, delamination in CFRP composites caused by drilling was investigated. The composite material was drilled under various spindle speeds, feed rates and drill point angles. The results showed that delamination and thrust forces were affected by cutting parameters. It was demonstrated that feed rate and drill point angle make the largest contribution to the overall performance.Öğe Mathematical modelling and optimization of cutting force, tool wear and surface roughness by using artificial neural network and response surface methodology in milling of Ti-6242S(Applied Sciences-Basel, 2017-10-15) Çelik, Yahya Hışman; Kılıçkap, Erol; Yardımeden, AhmetIn this paper, an experimental study was conducted to determine the effect of different cutting parameters such as cutting speed, feed rate, and depth of cut on cutting force, surface roughness, and tool wear in the milling of Ti-6242S alloy using the cemented carbide (WC) end mills with a 10 mm diameter. Data obtained from experiments were defined both Artificial Neural Network (ANN) and Response Surface Methodology (RSM). ANN trained network using Levenberg-Marquardt (LM) and weights were trained. On the other hand, the mathematical models in RSM were created applying Box Behnken design. Values obtained from the ANN and the RSM was found to be very close to the data obtained from experimental studies. The lowest cutting force and surface roughness were obtained at high cutting speeds and low feed rate and depth of cut. The minimum tool wear was obtained at low cutting speed, feed rate, and depth of cut.Öğe Investigation of experimental study of end milling of CFRP composite(De Gruyter, 2013-12-12) Çelik, Yahya Hışman; Kılıçkap, Erol; Yardımeden, AhmetCarbon fiber-reinforced plastic (CFRP) composites are materials that are difficult to machine due to the anisotropic and heterogeneous properties of the material and poor surface quality, which can be seen during the machining process. The machining of these materials causes delamination and surface roughness owing to excessive cutting forces. This causes the material not to be used. The reduction of damage and surface roughness is an important aspect for product quality. Therefore, the experimental study carried out on milling of CFRP composite material is of great importance. End milling tests were performed at CNC milling vertical machining center. In the experiments, parameters considered for the end milling of CFRP were cutting speed, feed rate, and flute number of end mill. The results showed that damage, surface roughness, and cutting forces were affected by cutting parameters and flute number of end mill. The best machining conditions were achieved at low feed rate and four-flute end mill.Öğe Karbon elyaf takviyeli plastik kompozitlerin tornalanmasında yüzey pürüzlülüğü ve takım aşınmasına etki eden parametrelerin araştırılması(Dicle Üniversitesi, 2017-03-01) Çelik, Yahya Hışman; Kılıçkap, Erol; Yardımeden, AhmetKarbon elyaf takviyeli plastik (KETP) kompozitler özellikle uzay ve havacılık başta olmak üzere birçok mühendislik uygulamalarında yaygın olarak kullanılan malzemelere alternatif olarak geniş ölçüde kullanım alanı bulmaktadır. Bu kompozit malzemelerin çeşitli amaçlarla kullanımından dolayı tornalama, frezeleme, delik delme gibi ikincil işlemlere de ihtiyaç duyulmaktadır. KETP kompozitlerin tornalanmasında oluşan yüzey pürüzlülüğü kesici takım malzemesi ve geometrisinden, işleme parametrelerinden, tezgâhın rijitliğinden, oluşan titreşimden, elyaf hasarı ve elyaf kopmasından etkilenmektedir. Ayrıca, takım aşınması da talaşlı işlemede çok önemli konulardandır. Takım aşınması takım ömrü, yüzey kalitesi ve üretim maliyetini doğrudan etkilemektedir. Takım aşınması iş parçası yüzey kalitesi ve iş parçasının toleranslar içerisinde üretilmesini de etkilemektedir. Bu çalışmada, KETP kompozitlerin TiAlN PVD kaplı takımla kuru tornalanmasında dönme devri ve ilerlemenin yüzey pürüzlüğü ve takım aşınması üzerine etkileri araştırılmıştır. Dönme devrindeki artış yüzey pürüzlülük değerinin iyileşmesine neden olurken ilerlemenin artması ile kötü bir yüzey elde edilmiştir. Kesici takım, tornalama zamanına bağlı olarak ilk başlarda hızlı aşınırken belirli bir aşınma değerinden sonra aşınma daha yavaş olmuşturÖğe Estimate of cutting forces and surface roughness in end milling of glass fiber reinforced plastic composites using fuzzy logic system(Walter de Gruyter, 2014-06-01) Çelik, Yahya Hışman; Kılıçkap, Erol; Yardımeden, AhmetMilling glass fiber reinforced plastic (GFRP) composite materials are problematic, owing to, e.g., nonhomogeneous and anisotropic properties and effects of plastic deformation. To reduce these problems, the effects of cutting speed, feed rate, and the number of flutes on surface roughness and of thrust forces occurring during the milling of GFRP composite materials were investigated by both experimental and fuzzy logic models. Experiments were performed at 30 m/min, 60 m/min, and 90 m/min cutting speeds, at 0.1 mm/rev, 0.15 mm/rev, and 0.2 mm/rev feed rates and 10 mm diameters in a cemented carbide end mill, which has two, three, and four flutes without cutting fluids. The values obtained from experiments were defined by a fuzzy logic model. A fuzzy logic model was employed to estimate the surface roughness and thrust forces for different cutting parameters. As a result of both the experimental study and the fuzzy logic model, while the minimum thrust force was obtained at low cutting speeds, and feed rates and a high number of flutes end mill, the best surface quality was obtained at low feed rates, high cutting speed, and number of flutes end mill.
