Halil İbrahim DEMİRCİ | Karabuk University (original) (raw)

Papers by Halil İbrahim DEMİRCİ

Materials & Design, 2006

Résumé/Abstract In this study, cylindrical cups formation of aluminium alloy sheets using a gas d... more Résumé/Abstract In this study, cylindrical cups formation of aluminium alloy sheets using a gas detonation forming system (DIN 99.5 (Etial 5)) was investigated. This system was achieved by accepting the volume ratio of acetylene (C 2 H 2)-oxygen (O 2) being equal, ...

Materials & Design, 2006

Résumé/Abstract In this study, cylindrical cups formation of aluminium alloy sheets using a gas d... more Résumé/Abstract In this study, cylindrical cups formation of aluminium alloy sheets using a gas detonation forming system (DIN 99.5 (Etial 5)) was investigated. This system was achieved by accepting the volume ratio of acetylene (C 2 H 2)-oxygen (O 2) being equal, ...

Gazi Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi, 2014

ABSTRACT ZET Eğimli yüzeylerin küresel parmak frezelenmesinde, değişken yüzey formu kesici takım ... more ABSTRACT ZET Eğimli yüzeylerin küresel parmak frezelenmesinde, değişken yüzey formu kesici takım üzerinde değişken kesme kuvvetlerine neden olmaktadır. Kesme kuvvetleriyle oluşan esnemeler parça üzerinde göz ardı edilemeyecek form hataları oluşturabilmektedir. Sehim değerlerinin ve buna bağlı form hatalarının bulunması, üretim için uygun toleranslar içinde kalınması ve maliyetlerin azaltılması açısından önem taşımaktadır. Çalışmada EN X40CrMoV5-1/DIN 1.2344 sıcak takım iş çeliğinin TiAlN kaplamalı küresel kesici ile dışbükey ve içbükey yüzeylerin frezelenmesinde takım sehimine bağlı form hatalarını değerlendirilmesi hedeflenmiştir. Farklı takım yolu stratejileri ve kesme parametrelerinin ilgili parametre seviye aralıklarında deneyler gerçekleştirilmiştir. Deneylerde endüktif sensörler ile işleme süresince dinamik takım sehimi kaydedilmiştir. 3B optik tarama ile işlenen deney numunelerin takım sehimine bağlı form hataları tespit edilmiştir. Ölçülen takım sehim değerleri ve 3B optik tarama form hata ölçüm değerleri karşılaştırılmıştır. Dışbükey ve içbükey yüzey formları için tırmanma bölgelerinde, frezeleme pozisyon açısının 45º ile 60º aralığında en fazla takım sehimi ve form hatası tespit edilmiştir. Aynı zamanda, en büyük sehimin oluştuğu bölgeler, optik taramalardan elde edilen en büyük form hata bölgelerinin olduğu gözlemlenmiştir. Çalışma sonucunda, kesici takım sehiminin neden olduğu form hatalarının tespitinde, dinamik ölçümlerinden elde edilen değerlerin optik tarama sonucunda elde edilen form hataları ile örtüştüğü görülmüştür. Anahtar kelimeler: Eğimli yüzeyler, küresel parmak frezeleme, takım sehimi, form hatası, optik tarama ABSTRACT Altering in surface forms cause to varying cutting forces in machining of inclined surfaces by ball end mills. The deflections appeared by cutting forces can result in form defects in workpiece. Finding deflection values and related form defects has a significant importance for keeping the production within the appropriate tolerances and in lessening production costs. The aim of this study is to evaluate form defects depending on tool deflection in milling of inclined convex and concave surfaces of EN X40CrMoV5-1/DIN 1.2344 using TiAlN-coated cutting tool. The experiments have been conducted with different cutting tools strategies and cutting parameters at related parameter levels. During machining real time cutting tool deflections are recorded by inductive sensors for the experiments. Then, the form defects of machined specimens caused by cutting tool deflections are determined by 3D optical scanning. The cutting tool deflection values and the values of 3D optical scanning form defects have been compared. The largest cutting tool deflections and form defects are detected at the ramping regions with the milling position angles of 45º to 60º for the convex and concave surface types. In addition, the regions that the largest tool deflections have been observed are the same regions with the largest form defects obtained by the optical scanning. As a result, at the determination of form defects caused by cutting tool deflection, the deflection values obtained by real time measurement are coincided with the measurement obtained from 3D optical scanning.

In 21. centuries' modern enterprises, system engineers have started to investigate the chaoti... more In 21. centuries' modern enterprises, system engineers have started to investigate the chaotic situations in the light of chaos theory by considering them in the earlier stages of the formation of manufacturing information systems. The purpose of this paper is to review chaos theory in order to motivate innovations in manufacturing enterprises and to examine the role that it may have in the discipline of the manufacturing information system and the management of an enterprise. In manufacturing information systems, data driven models based on alternative scenarios are developed according to chaos theory. The use of the chaos theory will contribute to the knowledge enhancement in manufacturing information systems' development and accelerate the transformation from complexity to incomplexity. The application of the chaos theory eases the controlling of the system, shorten manufacturing times, causes positive effect on the decreasing the cost and increasing the quality of the sy...

Journal of the Faculty of Engineering and Architecture of Gazi University

Altering in surface forms cause to varying cutting forces in machining of inclined surfaces by ba... more Altering in surface forms cause to varying cutting forces in machining of inclined surfaces by ball end mills. The deflections appeared by cutting forces can result in form defects in workpiece. Finding deflection values and related form defects has a significant importance for keeping the production within the appropriate tolerances and in lessening production costs. The aim of this study is to evaluate form defects depending on tool deflection in milling of inclined convex and concave surfaces of EN X40CrMoV5-1/DIN 1.2344 using TiAlN-coated cutting tool. The experiments have been conducted with different cutting tools strategies and cutting parameters at related parameter levels. During machining real time cutting tool deflections are recorded by inductive sensors for the experiments. Then, the form defects of machined specimens caused by cutting tool deflections are determined by 3D optical scanning. The cutting tool deflection values and the values of 3D optical scanning form de...

ARCHIVE Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering 1989-1996 (vols

The deflections appeared by cutting forces in ball end milling of inclined surfaces can result in... more The deflections appeared by cutting forces in ball end milling of inclined surfaces can result in defects in workpiece.

Transactions of FAMENA

The purpose of this study is to consider the effect of different parameters on the wrinkling phen... more The purpose of this study is to consider the effect of different parameters on the wrinkling phenomenon of square cups during the deep drawing process. An experimental system was prepared which consisted of a hydraulic press capable of applying different loads on the sheet metal blank and a blank holder and the process was controlled by a computer. All simulations were performed by using the ABAQUS/EXPLICIT V6.9 software, and the effect of different aluminium alloys, punch and die radius, blank holder force, blank holder gap, and friction coefficient on the wrinkling phenomenon has been investigated. Moreover, the minimal blank holder force was obtained by plotting minor strain with respect to the major strain of produced cups, and obtaining the maximum height of wrinkle in a cup. The wrinkling phenomenon was further investigated on different alloys such as A6111-T4, AA5754-O and Al-1050. The results imply that increasing the blank holder force and friction coefficient on the one ha...

Technology, 2011

This study investigates the diagonal tensile strength of frame-type constructed furniture corner ... more This study investigates the diagonal tensile strength of frame-type constructed furniture corner joints using four different joint elements; a plastic “L” corner joint, a minifix, a metal “T” joint, and a bent metal “T” pulling joint. The wooden material used in ...

The International Journal of Advanced Manufacturing Technology, 2013

Convex and concave inclined surfaces are frequently encountered in the machining of components in... more Convex and concave inclined surfaces are frequently encountered in the machining of components in industries such as aerospace, aircraft, automotive, biomedical, and precision machinery manufacturing and mold industries. Tool path styles, generated by different cutting strategies, result in various cutting forces and tool deflection values that might lead to poor surface integrities. In costeffective manufacturing, it is helpful to make known their effects on machinability. Thus, the first aim of this study is to investigate optimum cutting parameter values in ball end milling of EN X40CrMoV5-1 tool steel with three coated cutters. The parameters taken into consideration are cutting speed, feed rate, step over, and tool path style. The second aim of the study is to determine the effects of tool path styles in ball end milling of inclined surfaces. As a result, the most effective parameter within the selected cutting parameters and cutting styles for both inclined surfaces and different coatings was step over. In terms of tool coatings, the most rapidly deteriorating coating was TiC coating for cutting forces in both inclined surfaces and for tool deflection in convex inclined surface. In addition, the response surface methodology is employed to predict surface roughness values, depending on the cutting forces obtained. The model generated gives highly accurate results.

Otomotiv sektöründe, gövde imalatı ve diğer uygulamalarda, sac parça montajı için kullanılan bağl... more Otomotiv sektöründe, gövde imalatı ve diğer uygulamalarda, sac parça montajı için kullanılan bağlama aparatlarının imalatı günümüz rekabet ortamında gerekli hız, kalite ve ucuzluğu gerçekleştirebilecek kabiliyetini ancak işlerin planlı bir otomasyonu ve standardizasyonu ile sağlamaktadır. Bağlama aparatlarında, parçanın geometrik kısıtlamalarını tayin eden destek yerlerinin sayısı ve konumları, parçanın deforme olmuş şeklini ve ölçüsel değerlere etkisini belirlemektedir. Bu çalışmada; birbirine kaynak yöntemi ile birleştirilen sac parçaların bağlama aparatları üzerinde kendi ağırlığından dolayı oluşan sehimin minimum olduğu optimum destek noktalarının bulunarak kaynak operasyonları için hata oranının en aza indirilmesi hedeflenmiştir. Bu amaçla "Bağlama Noktası Optimizasyon Arayüzü" geliştirilerek sisteme entegre edilmiştir. Otomotiv sektöründe kullanılan bir sac parçanın kaynak ile birleştirme işlemi için gerekli bağlama noktaları incelenmiş, kullanılacak bağlama aparatlarının parça üzerindeki en ideal konumu geliştirilen makro yardımı ile bulunmuştur. Geliştirilen makronun endüstriyel uygulanabilirliği ortaya konulmuş endüstride maliyet ve zaman kazancı gibi olumlu etkiler sağladığı gözlenmiştir.

Tree-axis milling operations are often used in aeronautic, automotive and die/mould making indust... more Tree-axis milling operations are often used in aeronautic, automotive and die/mould making industries in order to machine complex surfaces. Size tolerances and surface integrity are very important in all of these operations. Cutting forces, which cause deflections at cutting tool and workpiece, result in worse workpiece quality. Therefore, the determination and diminishing of deflection values are crucial. A number of methods is employed in determination of deflection values. In this study, setting up a measurement system by using inductive sensors and dynamic deflection measurement at X-Y axes of a machine tool is elaborated.

Die parts used in automotive and aviation industry have complicated surfaces that require multiax... more Die parts used in automotive and aviation industry have complicated surfaces that require multiaxis machining. In machining of inclined surfaces with ball-end milling, the process is of great significance for its correctness and accuracy. In this study, Acoustic Sound Pressure (ASP) generated during the machining of a workpiece at a vertical machining centre has been measured. The experiments have been conducted in association with cutting velocity, feed rate and step over parameters determined by using different surface forms and different cutter path strategies. Therefore, the aim of this study is to understand the relationships between the generated sound signals and surface roughness in the machining of inclined concave and convex surfaces.

4th International Advanced Technologies …, Jan 1, 2005

Metallerin şekillendirilmesinde sacların plastik şekillendirilmesi önemli bir yer tutmaktadır. En... more Metallerin şekillendirilmesinde sacların plastik şekillendirilmesi önemli bir yer tutmaktadır. Endüstride kullanılan geleneksel sac şekillendirme teknikleri amprik metotlara dayalı, deneysel ve maliyetli yöntemlerdir. Şekillendirme sonuçlarının önceden tahmin edilmesi, uygulanacak zımba kuvvetinin, baskı plakası basıncının ve sac levhadaki kalınlık dağılımının belirlenmesi şekillendirilecek parçanın üretim maliyetini ve zamanını önemli ölçüde azaltacaktır. Bu amaçla non-lineer ekspilisit sonlu elemanlar metodu (ANSYS LS-DYNA) kullanılarak, temas modeli, malzeme özellikleri (AL 1050) ve Coulumb sürtünme katsayısı kullanılarak simulasyon gerçekleştirilmiş baskı plakasının cidar kalınlığına etkisi incelenmiştir. Elde edilen sonuçlar deneysel datalarla karşılaştırılarak % 90 uyum sağlandığı görülmüş, derin çekme işleminde kalıp üretilmeden önce karşılaşılabilecek problemler belirlenmiş ve çözüm önerileri sunulmuştur. ABSTRACT Plastic forming of sheets in metal processing has an importnat activity. Traditional sheet forming techniquesused in industry are based on amprical methods, experiencebased, and they are costly. Prediction of forming results before the process, determination of die force, pressure of blank holder and distribution of thickness on sheet decrease the cost production and the time. For these reason this paper describes an approach to identity the characteristics of thickness distrubution of AL 1050 of blank holder force on the drawing surface. Therein the major influence parameters are analysed such as thickness, coeficient of friction, materials parameters and blank holder force. The deep drawing deformation process has been simulated by using ANSYS LS-DYNA software. The results of the finite element simulations and the experiments are compared and showed that experimental results approximately 90 % agreement with the theoretical results and the problems to be faced of in deep drawing die which will be produced, predicted and solutions have been suggested before production.

mehmetfirat.net

The finite element modeling of aluminum cylindrical cup production with the detonation forming te... more The finite element modeling of aluminum cylindrical cup production with the detonation forming technology is performed. The forming process simulation is carried out in two-step analysis. 2-D and 3-D computational models are constructed and both explicit and implicit dynamic analyses are performed. The effects of detonation pressure and die design parameters are investigated. The thickness distribution and deformed geometry of the cup are compared with the experimentally determined values. The spring-back predictions based on the explicit and implicit methods are criticized in terms of deformed shape accuracy and computational cost.

mehmetfirat.net

Aluminum cylindrical cups are formed with gas detonation forming technology. Detonation forming o... more Aluminum cylindrical cups are formed with gas detonation forming technology. Detonation forming of the aluminum blank is performed in the developed combustion chamber. The forming process parameters are identified experimentally and their respective effects on the deformation of the blank are quantified. Deformation in the form of blank thinning and cup ruptured mainly take place during the first fourth of the process time. The effects of detonation pressure and blank holding force on the deformation of the workpieces are analyzed using finite element method and the numerical results are compared with those obtained in the experiments.

Journal of Alloys and Compounds, Jan 1, 2012

In this study, the wear behaviour of hot extruded Al-Si and Al-Mg alloys was investigated under d... more In this study, the wear behaviour of hot extruded Al-Si and Al-Mg alloys was investigated under dry conditions. Die cast Al-Mg alloy containing 1.7% Mg and Al-Si alloy containing 3.3% Si were extruded at 1.6 and 2 ratios. Mechanical and microstructural characterisations of the extruded alloys were carried out through optical microscopy, hardness measurements and tensile testing. Wear tests were carried out on a pin-on-disc type wear device and the worn surfaces were examined under a scanning electron microscope (SEM). The wear test results revealed that the extrusion ratio had an influence on the wear rate and that the samples extruded at a ratio of 1.6 had a lower wear resistance than the ones extruded at a ratio of 2.

Materials & Design, 2006

Résumé/Abstract In this study, cylindrical cups formation of aluminium alloy sheets using a gas d... more Résumé/Abstract In this study, cylindrical cups formation of aluminium alloy sheets using a gas detonation forming system (DIN 99.5 (Etial 5)) was investigated. This system was achieved by accepting the volume ratio of acetylene (C 2 H 2)-oxygen (O 2) being equal, ...

Materials & Design, 2006

Résumé/Abstract In this study, cylindrical cups formation of aluminium alloy sheets using a gas d... more Résumé/Abstract In this study, cylindrical cups formation of aluminium alloy sheets using a gas detonation forming system (DIN 99.5 (Etial 5)) was investigated. This system was achieved by accepting the volume ratio of acetylene (C 2 H 2)-oxygen (O 2) being equal, ...

Gazi Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi, 2014

ABSTRACT ZET Eğimli yüzeylerin küresel parmak frezelenmesinde, değişken yüzey formu kesici takım ... more ABSTRACT ZET Eğimli yüzeylerin küresel parmak frezelenmesinde, değişken yüzey formu kesici takım üzerinde değişken kesme kuvvetlerine neden olmaktadır. Kesme kuvvetleriyle oluşan esnemeler parça üzerinde göz ardı edilemeyecek form hataları oluşturabilmektedir. Sehim değerlerinin ve buna bağlı form hatalarının bulunması, üretim için uygun toleranslar içinde kalınması ve maliyetlerin azaltılması açısından önem taşımaktadır. Çalışmada EN X40CrMoV5-1/DIN 1.2344 sıcak takım iş çeliğinin TiAlN kaplamalı küresel kesici ile dışbükey ve içbükey yüzeylerin frezelenmesinde takım sehimine bağlı form hatalarını değerlendirilmesi hedeflenmiştir. Farklı takım yolu stratejileri ve kesme parametrelerinin ilgili parametre seviye aralıklarında deneyler gerçekleştirilmiştir. Deneylerde endüktif sensörler ile işleme süresince dinamik takım sehimi kaydedilmiştir. 3B optik tarama ile işlenen deney numunelerin takım sehimine bağlı form hataları tespit edilmiştir. Ölçülen takım sehim değerleri ve 3B optik tarama form hata ölçüm değerleri karşılaştırılmıştır. Dışbükey ve içbükey yüzey formları için tırmanma bölgelerinde, frezeleme pozisyon açısının 45º ile 60º aralığında en fazla takım sehimi ve form hatası tespit edilmiştir. Aynı zamanda, en büyük sehimin oluştuğu bölgeler, optik taramalardan elde edilen en büyük form hata bölgelerinin olduğu gözlemlenmiştir. Çalışma sonucunda, kesici takım sehiminin neden olduğu form hatalarının tespitinde, dinamik ölçümlerinden elde edilen değerlerin optik tarama sonucunda elde edilen form hataları ile örtüştüğü görülmüştür. Anahtar kelimeler: Eğimli yüzeyler, küresel parmak frezeleme, takım sehimi, form hatası, optik tarama ABSTRACT Altering in surface forms cause to varying cutting forces in machining of inclined surfaces by ball end mills. The deflections appeared by cutting forces can result in form defects in workpiece. Finding deflection values and related form defects has a significant importance for keeping the production within the appropriate tolerances and in lessening production costs. The aim of this study is to evaluate form defects depending on tool deflection in milling of inclined convex and concave surfaces of EN X40CrMoV5-1/DIN 1.2344 using TiAlN-coated cutting tool. The experiments have been conducted with different cutting tools strategies and cutting parameters at related parameter levels. During machining real time cutting tool deflections are recorded by inductive sensors for the experiments. Then, the form defects of machined specimens caused by cutting tool deflections are determined by 3D optical scanning. The cutting tool deflection values and the values of 3D optical scanning form defects have been compared. The largest cutting tool deflections and form defects are detected at the ramping regions with the milling position angles of 45º to 60º for the convex and concave surface types. In addition, the regions that the largest tool deflections have been observed are the same regions with the largest form defects obtained by the optical scanning. As a result, at the determination of form defects caused by cutting tool deflection, the deflection values obtained by real time measurement are coincided with the measurement obtained from 3D optical scanning.

In 21. centuries' modern enterprises, system engineers have started to investigate the chaoti... more In 21. centuries' modern enterprises, system engineers have started to investigate the chaotic situations in the light of chaos theory by considering them in the earlier stages of the formation of manufacturing information systems. The purpose of this paper is to review chaos theory in order to motivate innovations in manufacturing enterprises and to examine the role that it may have in the discipline of the manufacturing information system and the management of an enterprise. In manufacturing information systems, data driven models based on alternative scenarios are developed according to chaos theory. The use of the chaos theory will contribute to the knowledge enhancement in manufacturing information systems' development and accelerate the transformation from complexity to incomplexity. The application of the chaos theory eases the controlling of the system, shorten manufacturing times, causes positive effect on the decreasing the cost and increasing the quality of the sy...

Journal of the Faculty of Engineering and Architecture of Gazi University

Altering in surface forms cause to varying cutting forces in machining of inclined surfaces by ba... more Altering in surface forms cause to varying cutting forces in machining of inclined surfaces by ball end mills. The deflections appeared by cutting forces can result in form defects in workpiece. Finding deflection values and related form defects has a significant importance for keeping the production within the appropriate tolerances and in lessening production costs. The aim of this study is to evaluate form defects depending on tool deflection in milling of inclined convex and concave surfaces of EN X40CrMoV5-1/DIN 1.2344 using TiAlN-coated cutting tool. The experiments have been conducted with different cutting tools strategies and cutting parameters at related parameter levels. During machining real time cutting tool deflections are recorded by inductive sensors for the experiments. Then, the form defects of machined specimens caused by cutting tool deflections are determined by 3D optical scanning. The cutting tool deflection values and the values of 3D optical scanning form de...

ARCHIVE Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering 1989-1996 (vols

The deflections appeared by cutting forces in ball end milling of inclined surfaces can result in... more The deflections appeared by cutting forces in ball end milling of inclined surfaces can result in defects in workpiece.

Transactions of FAMENA

The purpose of this study is to consider the effect of different parameters on the wrinkling phen... more The purpose of this study is to consider the effect of different parameters on the wrinkling phenomenon of square cups during the deep drawing process. An experimental system was prepared which consisted of a hydraulic press capable of applying different loads on the sheet metal blank and a blank holder and the process was controlled by a computer. All simulations were performed by using the ABAQUS/EXPLICIT V6.9 software, and the effect of different aluminium alloys, punch and die radius, blank holder force, blank holder gap, and friction coefficient on the wrinkling phenomenon has been investigated. Moreover, the minimal blank holder force was obtained by plotting minor strain with respect to the major strain of produced cups, and obtaining the maximum height of wrinkle in a cup. The wrinkling phenomenon was further investigated on different alloys such as A6111-T4, AA5754-O and Al-1050. The results imply that increasing the blank holder force and friction coefficient on the one ha...

Technology, 2011

This study investigates the diagonal tensile strength of frame-type constructed furniture corner ... more This study investigates the diagonal tensile strength of frame-type constructed furniture corner joints using four different joint elements; a plastic “L” corner joint, a minifix, a metal “T” joint, and a bent metal “T” pulling joint. The wooden material used in ...

The International Journal of Advanced Manufacturing Technology, 2013

Convex and concave inclined surfaces are frequently encountered in the machining of components in... more Convex and concave inclined surfaces are frequently encountered in the machining of components in industries such as aerospace, aircraft, automotive, biomedical, and precision machinery manufacturing and mold industries. Tool path styles, generated by different cutting strategies, result in various cutting forces and tool deflection values that might lead to poor surface integrities. In costeffective manufacturing, it is helpful to make known their effects on machinability. Thus, the first aim of this study is to investigate optimum cutting parameter values in ball end milling of EN X40CrMoV5-1 tool steel with three coated cutters. The parameters taken into consideration are cutting speed, feed rate, step over, and tool path style. The second aim of the study is to determine the effects of tool path styles in ball end milling of inclined surfaces. As a result, the most effective parameter within the selected cutting parameters and cutting styles for both inclined surfaces and different coatings was step over. In terms of tool coatings, the most rapidly deteriorating coating was TiC coating for cutting forces in both inclined surfaces and for tool deflection in convex inclined surface. In addition, the response surface methodology is employed to predict surface roughness values, depending on the cutting forces obtained. The model generated gives highly accurate results.

Otomotiv sektöründe, gövde imalatı ve diğer uygulamalarda, sac parça montajı için kullanılan bağl... more Otomotiv sektöründe, gövde imalatı ve diğer uygulamalarda, sac parça montajı için kullanılan bağlama aparatlarının imalatı günümüz rekabet ortamında gerekli hız, kalite ve ucuzluğu gerçekleştirebilecek kabiliyetini ancak işlerin planlı bir otomasyonu ve standardizasyonu ile sağlamaktadır. Bağlama aparatlarında, parçanın geometrik kısıtlamalarını tayin eden destek yerlerinin sayısı ve konumları, parçanın deforme olmuş şeklini ve ölçüsel değerlere etkisini belirlemektedir. Bu çalışmada; birbirine kaynak yöntemi ile birleştirilen sac parçaların bağlama aparatları üzerinde kendi ağırlığından dolayı oluşan sehimin minimum olduğu optimum destek noktalarının bulunarak kaynak operasyonları için hata oranının en aza indirilmesi hedeflenmiştir. Bu amaçla "Bağlama Noktası Optimizasyon Arayüzü" geliştirilerek sisteme entegre edilmiştir. Otomotiv sektöründe kullanılan bir sac parçanın kaynak ile birleştirme işlemi için gerekli bağlama noktaları incelenmiş, kullanılacak bağlama aparatlarının parça üzerindeki en ideal konumu geliştirilen makro yardımı ile bulunmuştur. Geliştirilen makronun endüstriyel uygulanabilirliği ortaya konulmuş endüstride maliyet ve zaman kazancı gibi olumlu etkiler sağladığı gözlenmiştir.

Tree-axis milling operations are often used in aeronautic, automotive and die/mould making indust... more Tree-axis milling operations are often used in aeronautic, automotive and die/mould making industries in order to machine complex surfaces. Size tolerances and surface integrity are very important in all of these operations. Cutting forces, which cause deflections at cutting tool and workpiece, result in worse workpiece quality. Therefore, the determination and diminishing of deflection values are crucial. A number of methods is employed in determination of deflection values. In this study, setting up a measurement system by using inductive sensors and dynamic deflection measurement at X-Y axes of a machine tool is elaborated.

Die parts used in automotive and aviation industry have complicated surfaces that require multiax... more Die parts used in automotive and aviation industry have complicated surfaces that require multiaxis machining. In machining of inclined surfaces with ball-end milling, the process is of great significance for its correctness and accuracy. In this study, Acoustic Sound Pressure (ASP) generated during the machining of a workpiece at a vertical machining centre has been measured. The experiments have been conducted in association with cutting velocity, feed rate and step over parameters determined by using different surface forms and different cutter path strategies. Therefore, the aim of this study is to understand the relationships between the generated sound signals and surface roughness in the machining of inclined concave and convex surfaces.

4th International Advanced Technologies …, Jan 1, 2005

Metallerin şekillendirilmesinde sacların plastik şekillendirilmesi önemli bir yer tutmaktadır. En... more Metallerin şekillendirilmesinde sacların plastik şekillendirilmesi önemli bir yer tutmaktadır. Endüstride kullanılan geleneksel sac şekillendirme teknikleri amprik metotlara dayalı, deneysel ve maliyetli yöntemlerdir. Şekillendirme sonuçlarının önceden tahmin edilmesi, uygulanacak zımba kuvvetinin, baskı plakası basıncının ve sac levhadaki kalınlık dağılımının belirlenmesi şekillendirilecek parçanın üretim maliyetini ve zamanını önemli ölçüde azaltacaktır. Bu amaçla non-lineer ekspilisit sonlu elemanlar metodu (ANSYS LS-DYNA) kullanılarak, temas modeli, malzeme özellikleri (AL 1050) ve Coulumb sürtünme katsayısı kullanılarak simulasyon gerçekleştirilmiş baskı plakasının cidar kalınlığına etkisi incelenmiştir. Elde edilen sonuçlar deneysel datalarla karşılaştırılarak % 90 uyum sağlandığı görülmüş, derin çekme işleminde kalıp üretilmeden önce karşılaşılabilecek problemler belirlenmiş ve çözüm önerileri sunulmuştur. ABSTRACT Plastic forming of sheets in metal processing has an importnat activity. Traditional sheet forming techniquesused in industry are based on amprical methods, experiencebased, and they are costly. Prediction of forming results before the process, determination of die force, pressure of blank holder and distribution of thickness on sheet decrease the cost production and the time. For these reason this paper describes an approach to identity the characteristics of thickness distrubution of AL 1050 of blank holder force on the drawing surface. Therein the major influence parameters are analysed such as thickness, coeficient of friction, materials parameters and blank holder force. The deep drawing deformation process has been simulated by using ANSYS LS-DYNA software. The results of the finite element simulations and the experiments are compared and showed that experimental results approximately 90 % agreement with the theoretical results and the problems to be faced of in deep drawing die which will be produced, predicted and solutions have been suggested before production.

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The finite element modeling of aluminum cylindrical cup production with the detonation forming te... more The finite element modeling of aluminum cylindrical cup production with the detonation forming technology is performed. The forming process simulation is carried out in two-step analysis. 2-D and 3-D computational models are constructed and both explicit and implicit dynamic analyses are performed. The effects of detonation pressure and die design parameters are investigated. The thickness distribution and deformed geometry of the cup are compared with the experimentally determined values. The spring-back predictions based on the explicit and implicit methods are criticized in terms of deformed shape accuracy and computational cost.

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Aluminum cylindrical cups are formed with gas detonation forming technology. Detonation forming o... more Aluminum cylindrical cups are formed with gas detonation forming technology. Detonation forming of the aluminum blank is performed in the developed combustion chamber. The forming process parameters are identified experimentally and their respective effects on the deformation of the blank are quantified. Deformation in the form of blank thinning and cup ruptured mainly take place during the first fourth of the process time. The effects of detonation pressure and blank holding force on the deformation of the workpieces are analyzed using finite element method and the numerical results are compared with those obtained in the experiments.

Journal of Alloys and Compounds, Jan 1, 2012

In this study, the wear behaviour of hot extruded Al-Si and Al-Mg alloys was investigated under d... more In this study, the wear behaviour of hot extruded Al-Si and Al-Mg alloys was investigated under dry conditions. Die cast Al-Mg alloy containing 1.7% Mg and Al-Si alloy containing 3.3% Si were extruded at 1.6 and 2 ratios. Mechanical and microstructural characterisations of the extruded alloys were carried out through optical microscopy, hardness measurements and tensile testing. Wear tests were carried out on a pin-on-disc type wear device and the worn surfaces were examined under a scanning electron microscope (SEM). The wear test results revealed that the extrusion ratio had an influence on the wear rate and that the samples extruded at a ratio of 1.6 had a lower wear resistance than the ones extruded at a ratio of 2.