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Yayın Mechanical and thermal modeling of orthogonal turn-milling operation(Elsevier Science BV, 2017) Karagüzel, Umut; Bakkal, Mustafa; Budak, ErhanTurn-milling is a relatively new machining technology which is performed for cutting of symmetrical or non-symmetrical rotational parts. To improve productivity, determination of cutting parameters in turn-milling is crucial. However, experimental approach is costly, hence it is important to develop predictive models, especially analytical models, for improved process outputs such as cutting force, MRR, cutting temperature etc. In this study, cutting forces, part quality, MRR, cutting temperatures are modeled for orthogonal turn-milling operation. The developed models are verified by experiments. The results show that the eccentricity parameter in turn-milling has a significant effect on process outputs.Yayın Investigation and prediction of surface integrity induced by milling of hot forged and heat treated AA7075(Motto, 2024-11-03) Tok, Görkem; Dinçer, Ammar Tarık; Kuzu, Ali Taner; Bakkal, Mustafa; Saklakoğlu, İ. EtemThis study examines the influence of cutting parameters on surface integrity, focusing on residual stress and surface roughness, in hot-forged and T6 heat-treated AA7075 components post-milling. Using the Taguchi L9 DOE method, orthogonal cutting milling experiments were performed, with residual stress measured via nondestructive X-ray diffraction (XRD). The analysis indicated that lower cutting speeds reduce residual stress, with down milling causing compressive and up milling causing tensile stresses. A proposed model showed a significant correlation between cutting force and residual stress—higher cutting forces increased residual stress. Surface roughness assessment revealed that feed rate greatly impacts residual stress, with lower feed rates reducing roughness. These insights will aid in developing a regression model for predicting outcomes in future experiments, enhancing the understanding and control of surface integrity in milling AA7075 components.Yayın Material replacement and topology optimization study on a PVC cutting machine component(TICMET Organizing Committee, 2011-11-03) Hançerkıran, Zeynep; Ahlatcı, Umut Can; Topuzoğlu, Ertan; Kasapcopur, Taylan; Alkan, Erkan; Ertürk, Fikret; Karagüzel, Umut; Bakkal, MustafaIn this study, it is aimed to lighten the aluminum body of the PVC cutting machine, reduce the production cost and shorten the production time. With this purpose, firstly, literature researches of composite materials were made and the PVC machine was introduced. Then, alternative designs of this body were made in Fusion360, and material selection was discussed in line with the analyzes made on the designs in ANSYS. Designs of this body were reexamined by topology optimization of designs created with selected materials. Test and analyzes are shown step-by-step in order to achieve the final result with the necessary changes to mitigate. As a result the body part has lightened up to %70 with the choice of different materials and design.Yayın Zirkonyum esaslı kalın camsı metalin taşlanmasında kesme sıcaklıkları ve enerji paylaşımı(UTIS Organizing Committee, 2017-11-02) Timur, Azmi; Karipçin, İlker; Karagüzel, Umut; Kuzu, Ali Taner; Bakkal, MustafaBu çalışmada talaşlı imalat işlemleri arasında özgül enerjinin en yüksek olduğu ve ısıyla ilgili problemlerin en çok yaşandığı “taşlama” işleminin farklı taş ve işleme parametrelerinin zirkonyum esaslı Kalın Camsı Metal’nin [KCM] amorf yapısına metalürjik etkileri, meydana gelen taşlama sıcaklıkları, enerjinin ne kadarının KCM’ye geçtiği araştırılmıştır. Seçilen alaşım Vitreloy 105 ticari ismine sahip ve Zr52,5Ti5Cu17,9Ni14,6Al10 bileşimindeki Zr-esaslı KCM’dir. 6.35 mm çapa sahip dairesel kesitli Zr-esaslı KCM çubukların yüzey ve yüzey altı sıcaklıkları gömme termokupl yöntemi ile ölçülmüş ve ardından içyapı Xışını difraksiyonu ile analiz edilmiştir. Bunların yanında iş parçasına ısı şeklinde geçen enerjinin taşlama sırasında harcanan toplam enerjiye oranı olarak ifade edilen enerji paylaşımı hesaplanmıştır. Bu hesaplarda kullanılmak üzere kuvvet ölçümü de yapılmıştır. İlerleme hızı ve paso kalınlığı sabit tutularak farklı kesme hızında taşlama testleri yapılmıştır. Sabit kesme hızı ve paso kalınlığında ve farklı ilerleme hızında yapılan testlerde sıcaklıkların değişimi farklı bir eğilim göstermiştir. Daha sonra kesme hızı ve ilerleme hızı sabit tutulup paso kalınlığı arttırılmıştır. Bütün bu deneylerde CBN aşındırıcılı taş kullanılırken, aşındırıcı malzemesinin sıcaklıklara olan etkisini görebilmek için son olarak CBN yerine Al2O3 aşındırıcılı taş kullanılarak bir test daha yapılmıştır. Bütün taşlanan numunelerde X-ışını difraksiyonu analizi yapılarak kristalleşme olup olmadığı belirlenmiş ve sonuçlar ölçülen sıcaklıklarla ilişkilendirilmiştir. Son olarak bütün testler için enerji paylaşımı değerleri hesaplanmıştır ve bu değerlerin kesme parametreleri ve aşındırıcı malzemesiyle değişimi incelenmiştir.Yayın Effect of cutting strategy on machining of thin walled polymer(UTIS Organizing Committee, 2017-11-02) Keklik, Burak Taha; Kuzu, Ali Taner; Başçı, Ümit Gencay; Karagüzel, Umut; Kayıhan, Mete; Bakkal, MustafaThis paper presents the effect of tool path on machining of thin walled thermoplastic polymer, ABS. The effects of cutting speed, feed rate and tool path are studied to evaluate surface quality on thin walled parts. Four different cutting pattern (“zig”, “zig-zag”, “follow periphery” and “trochoidal”) with uncoated WC tool were investigated in the cutting tests. The quality of grooves was examined by their surface roughness, dimensional accuracy and burr structure. Experiments show that the down-milling and “follow periphery” creates dimensionally more accurate grooves. Average 4 μm surface roughness and discontinuous chip formation is obtained in up-milling process. According to the study, the better surface quality and dimensional accuracy can be achieved by down milling in “zig-zag” pattern in terms of surface roughness.Yayın Dairesel testere makine parametrelerinin yüzey kalitesine etkisi incelenmesi(Motto, 2024-11-03) Çakır, Hasan; Yılmaz, Mahmut; Yeter, Alper; Karagüzel, Umut; Kuzu, Ali Taner; Bakkal, Mustafa; Saklakoğlu, İ. EtemDairesel testere ile yapılan kesimlerde gelişen teknolojiyle birlikte kesilen yüzeylerde yüksek yüzey kalitesi beklentisi artmıştır. Yüzey kalitesine kesme işleme sırasında kullanılan dairesel testere ve testere malzeme yapısı doğrudan etki etmektedir. Aynı zamanda makine çalışma parametreleri de yüzey kalitesine etki etmektedir. Yapılan bu çalışmada makine çalışma parametreleri içersinde yer alan ilerleme ve kesme hızlarında, farklı değerler kullanılarak kesme deneyleri yapılmıştır. Deneyler veri toplama cihazı ile makine gövdesi üzerine yerleştirilen ivmeölçer sensörlerden titreşim verileri toplanmıştır. Toplanan veriler, veri toplama cihazı arayüz programında işlenerek maksimum ivme değerleri ve ivmelerin ortalama karekök değerleri hesaplanmıştır. Hesaplanan veriler ile krest faktörünün farklı ilerleme ve kesim hızlarında değeri bulunmuştur. Yüzey pürüzlülük ölçüm cihazı kullanılarak kesim yapılan parçaların yüzey pürüzlülük değeri tespit edilmiştir. Deneyler sonucunda makinede meydana gelen titreşimlerin yüzey pürüzlülüğüne olan etkisi araştırılmıştır.Yayın Experimental and analytical investigation of drilling in high performance hybrid composites(2019-11-09) Kayıhan, Mete; Karagüzel, Umut; Bakkal, MustafaHybrid composites produced by the addition of metal alloys to carbon fiber reinforced composites (CFRP) have superior mechanical and physical properties, excellent specific strength and high resistance to corrosion. The most commonly used machining processes in the use of hybrid materials in industry is the drilling process. After the drilling processes, due to the anisotropic properties of the CFRP material, delamination, uncut fiber and fiber pullout are observed. For this reason, the performance of CFRP after drilling operation must be the main concern. Therefore, in this study, hybrid materials were tested on factors such as stack order, drilling speed and feed rate which should be applied in hole drilling process and analysis were made on various results. The tests were performed with three-factor and three-level L9 Taguchi orthogonal experiment design due to minimize the cost and material. As a result of this study, the best stack order and drilling parameters of the hybrid composite materials was determined with many variables such as force and torque values, the required energy, surface roughness values and delamination factors.Yayın Investigation of process parameters in rotary swaging(TICMET, 2023-11-16) Bakkal, Mustafa; Karagüzel, Umut; Kuzu, Ali Taner; Kurt, Hasan Aytuğ; Çakır, HasanRotary swaging is a metalworking process used to reduce the diameter of a cylindrical workpiece or to shape it into a desired form. It is a cold-forming process, meaning it is carried out at room temperature or slightly elevated temperatures without the need for additional heat. Rotary swaging is particularly useful for creating components with a taper or complex geometries. In this study, focusing on an effects of die angle and feeding rate upon specified tubular geometry which have 2 mm thickness. An identified load was applied to the tubular geometry in Simufact finite element software for 3 different die angles and feed rates. As a result, optimum die angle and feed rate were determined.Yayın Effects of different production parameters on mechanical properties in FDM-printed products(Eklemeli İmalat Derneği Yayınları, 2022-10-08) Kösemen, Elifnur; Kuzu, Ali Taner; Bakkal, MustafaFDM, which is a common additive manufacturing technology in producing plastic parts, allows for the comparison of many different production parameters. This article presents the variation of density, hardness, tensile and impact strength depending on the production parameters of the number of contours, infill pattern and orientation angle. 8 different production parameter combinations were created using 2 diff erent contour numbers as 1 and 2, 2 different infill patterns as sparse high density and hexagram, and two different orientation angles as 0o/45o degrees, and sample production was made with FDM technology and ABS material. In the experiments performed on the samples produced with the specified production combinations, no major change in density and hardness was detected, and it was determined that the production parameter combination that gave the best results in both tensile and impact strength was hexagram infill pattern, 45o orientation angle and 2 contour production parameters.
