CFRP/Al-7075 istifli delmede matkap uç açılarının delinebilirlik üzerine etkisi

Bu çalışmada, askeri ve sivil havacılık alanında yoğun olarak kullanılmakta olan karbon fiber takviyelipolimer kompozit (CFRP) malzeme ve Al-7075 alaşımının oluşturduğu CFRP/Al-7075 istifli yapının, 120º-130º-140º uç açılarına sahip kaplamasız karbür matkaplar ile delinebilirliği araştırılmıştır. Delmesüreçlerinde itme kuvveti (Fz), moment (Mz), delik ortalama yüzey pürüzlülükleri (Ra), talaş yapıları ve CFRP malzemede meydana gelen delaminasyonlar (Fd) incelenmiştir. Deneysel çalışmalar kuru kesmeşartlarında 50 m/min kesme hızı ve 0,05 mm/dev sabit ilerleme değerinde, doğrudan delme yöntemindegerçekleştirilmiştir. 120° ve 130° uç açılı matkaplar CFRP malzemede yakın Fz ve Fd değerleri sergilerken, uç açılarına göre en düşük Fz, Mz, Ra ve en düşük Fd verileri sırasıyla 130°-120º-140º uç açılı matkaplarda elde edilmiştir. 140° uç açılı matkapta, esas kesici kenarda yoğun miktarda çapaklanma ve yığıntı talaş (Builtup edge BUE) meydana gelmiş ayrıca matkap helis kanallarında Al talaşları sıvanmıştır. Deneyselçalışmaların ardından matkap uç açılarının itme kuvveti (Fz) ve ortalama yüzey pürüzlülüğü (Ra) üzerine etkileri %95 güven aralığında ANOVA ile belirlenmiş ve çoklu karşılaştırma testleri uygulanmıştır. Sonuç olarak, 130º uç açılı kaplamasız karbür matkabın moment, itme kuvveti, ortalama yüzey pürüzlülüğü vedelaminasyon bakımından belirtilen kesme parametreleri ve delme koşulları doğrultusunda CFRP/Al-7075 istifli delme işleminde daha iyi sonuçlar verdiği görülmüştürIn this study, the drillability of CFRP/Al-7075 stacked structure which is formed by carbon fiber reinforcedpolymer composite (CFRP) material, which is used intensively in the field of military and civil aviation, andAl-7075 alloy has been investigated by drilling with uncoated carbide drills with different point angles. Inthe drilling processes thrust force (Fz), moment (Mz), hole average surface roughness (Ra), chip structure anddelamination (Fd) occurring in CFRP material were investigated. Experimental studies were performed underdry cutting conditions with 50 m/min cutting speed and 0.05 mm/rev constant feed rate by using threedifferent drill (120º-130º-140º) point angles uncoated carbide drills have different. 120° and 130° point angle drills are showed close Fz and Fd values in the CFRP material, while the lowest Fz, Mz, Ra and lowest Fdvalue are obtained respectively in 130°-120º-140º point angle drills. In the 140° point angle drill, a largeamount of burring and built-up edge (BUE) was formed on the main cutting edge and Al chips were plasteredin the drill helix flutes. After experimental studies, the effects of drill point angles on thrust force and averagesurface roughness were determined by ANOVA at 95% confidence interval and multiple comparison testswere applied. As a result, it has been seen that uncoated carbide drill has 130º point angle gives better results in terms of moment, thrust force, average surface roughness and delamination, under specified cuttingparameters and drilling conditions in CFRP/Al-7075 stacking drilling

Investigating the effects of cutting speeds over the built-up layer and built-up edge formation with SEM

Bu çalışmada, işleme parametrelerinden kesme hızının Yığıntı Katmanı (Built-Up layer) (YK) ve Yığıntı Talaş (Built-Up Edge) (YT) oluşumu üzerindeki etkileri araştırılmıştır. Bu amaçla, AA5052 alaşımı; kaplamasız karbür takımla bilgisayarlı sayısal denetimli (BSD) torna tezgahında, kuru olarak işlenmiştir. Deneylerde, beş farklı kesme hızı (100, 200, 300, 400, 500 m/min), sabit ilerleme hızı (0,30 mm/dev) ve sabit kesme derinliği (1.5 mm) işleme parametreleri olarak seçilmiştir. Talaş kaldırma işlemleri sonucunda, kesici takım üzerinde en fazla YK ve YT, 100 m/min kesme hızı ve 0,30 mm/dev ilerleme hızında yapılan talaş kaldırma işleminde oluştuğu tespit edilmiştir. Kesme hızının artırılması YK ve YT oluşumunu azaltmış, fakat denenen sınırlar içerisinde YK ve YT oluşumu engellenememiştir.In this study, the effects of cutting speed; over the formation of Built-Up Layer (BUL) and Built-Up Edge (BUE) were investigated. For this purpose, AA5052 alloy was processed on a Computer Numeric Control (CNC) lathe with uncoated cemented carbide insert in dry conditions. As processing parameters in the experiments, five different cutting speeds (100, 200, 300, 400, 500 m/min), constant feed rate (0,30 mm/rev) and connstant depth of cut (1,5 mm) were selected. As the result of the experiments, it was stated that BUL and BUE were formed on cutting tool mostly in machining at 100 m/min cutting speed and 0,30 mm/rev feed rate. Increasing the cutting speed decreased BUL and BUE formation but they could not be stopped in the tested range

Titreşim Fikstürlerinde Vibrasyon Ölçümleriyle Sonlu Elemanlar Model Sonuçlarının Karşılaştırılması

maummfdBu çalışmada, titreşim testleri sırasında sarsıcı ve test edilecek ürün arasında titreşimin kayıpsız iletilmesini amaçlayan bir titreşim fikstürü tasarlanmıştır. Tasarlanan titreşim fikstürü Al 6061 serisi ve St52 çelik malzemeler kullanılarak üretilmiştir. Tasarım, ANSYS paket programı kullanılarak ve MIL-HNDBK-2164A askeri standardında yer alan rastsal titreşim profili için uygun fikstür limitleri sağlanarak tamamlanmıştır. Analizler doğrultusunda titreşim fikstürü imal edilmiştir. İmal edilen bu titreşim fikstürü sarsıcının dikey eksen tertibatına bağlanarak üzerinden ivme ölçerlerle veriler alınmıştır. Analiz sonuçları ve deneysel sonuçlar karşılaştırılmıştır. Yapılan rastsal titreşim analizlerindeki GRMS değerlerinin oranları incelendiğinde, bu oranların 1, 043 olduğu görülmüştür. Titreşim fikstürünün rastsal titreşim testlerinde bazı frekans aralıklarında titreşim profilini tam olarak iletemese de titreşim kaynaklı enerjiyi başarılı bir şekilde ileteceği değerlendirilmiştir.102703

CFRP/Al-7075 istifli delmede matkap uç açılarının delinebilirlik üzerine etkisi

In this study, the drillability of CFRP/Al-7075 stacked structure which is formed by carbon fiber reinforced polymer composite (CFRP) material, which is used intensively in the field of military and civil aviation, and Al-7075 alloy has been investigated by drilling with uncoated carbide drills with different point angles. In the drilling processes thrust force (F-z), moment (M-z), hole average surface roughness (R-a), chip structure and delamination (Fa) occurring in CFRP material were investigated. Experimental studies were performed under dry cutting conditions with 50 m/min cutting speed and 0.05 mm/rev constant feed rate by using three different drill (120 degrees-130 degrees-140 degrees) point angles uncoated carbide drills have different. 120 degrees and 130 degrees point angle drills are showed close F-z and F-d values in the CFRP material, while the lowest F-z, M-z, R-a and lowest F-d value are obtained respectively in 130 degrees-120 degrees-140 degrees point angle drills. In the 140 degrees point angle drill, a large amount of burring and built-up edge (BUE) was formed on the main cutting edge and Al chips were plastered in the drill helix flutes. After experimental studies, the effects of drill point angles on thrust force and average surface roughness were determined by ANOVA at 95\% confidence interval and multiple comparison tests were applied. As a result, it has been seen that uncoated carbide drill has 130 degrees point angle gives better results in terms of moment, thrust force, average surface roughness and delamination, under specified cutting parameters and drilling conditions in CFRP/Al-7075 stacking drilling

Comparison of Regression and Artificial Neural Network Models for Surface Roughness Prediction with the Cutting Parameters in CNC Turning

Surface roughness, an indicator of surface quality, is one of the most specified customer requirements in machining of parts. In this study, the experimental results corresponding to the effects of different insert nose radii of cutting tools (0.4, 0.8, 1.2 mm), various depth of cuts (0.75, 1.25, 1.75, 2.25, 2.75 mm), and different feedrates (100, 130, 160, 190, 220 mm/min) on the surface quality of the AISI 1030 steel workpieces have been investigated using multiple regression analysis and artificial neural networks (ANN). Regression analysis and neural network-based models used for the prediction of surface roughness were compared for various cutting conditions in turning. The data set obtained from the measurements of surface roughness was employed to and tests the neural network model. The trained neural network models were used in predicting surface roughness for cutting conditions. A comparison of neural network models with regression model was carried out. Coefficient of determination was 0.98 in multiple regression model. The scaled conjugate gradient (SCG) model with 9 neurons in hidden layer has produced absolute fraction of variance (R2) values of 0.999 for the training data, and 0.998 for the test data. Predictive neural network model showed better predictions than various regression models for surface roughness. However, both methods can be used for the prediction of surface roughness in turning

The effect of coating material and geometry of cutting tool and cutting speed on machinability properties of Inconel 718 super alloys

In this study, the effects of cutting tool coating material and cutting speed on cutting forces and surface roughness are investigated. For this purpose, nickel based super alloy Inconel 718 is machined at dry cutting conditions with three different cemented carbide tools in CNC lathe. Metal removing process is carried out for five different cutting speeds (15, 30, 45, 60, 75 m/min.) while 2 mm depth of cut and 0.20 mm/rev feed rate are to be constant. Main cutting force, Fc is considered to be cutting force as a criterion. In the experiments, depending on the tool coating material, lowest main cutting force is found to be 506 N at 75 m/min with multicoated cemented carbide insert whose top layer is coated by Al2O3. Lowest average surface roughness (0.806 µm) is obtained at the cutting speed of 15 m/min with single coated (TiN) cemented carbide inserts. © 2006 Elsevier Ltd. All rights reserved

Hindawi Publishing Corporation Modelling and Simulation in Engineering Volume

Surface roughness, an indicator of surface quality, is one of the most specified customer requirements in machining of parts. In this study, the experimental results corresponding to the effects of different insert nose radii of cutting tools (0.4, 0.8, 1.2 mm), various depth of cuts (0.75, 1.25, 1.75, 2.25, 2.75 mm), and different feedrates (100, 130, 160, 190, 220 mm/min) on the surface quality of the AISI 1030 steel workpieces have been investigated using multiple regression analysis and artificial neural networks (ANN). Regression analysis and neural network-based models used for the prediction of surface roughness were compared for various cutting conditions in turning. The data set obtained from the measurements of surface roughness was employed to and tests the neural network model. The trained neural network models were used in predicting surface roughness for cutting conditions. A comparison of neural network models with regression model was carried out. Coefficient of determination was 0.98 in multiple regression model. The scaled conjugate gradient (SCG) model with 9 neurons in hidden layer has produced absolute fraction of variance (R 2 ) values of 0.999 for the training data, and 0.998 for the test data. Predictive neural network model showed better predictions than various regression models for surface roughness. However, both methods can be used for the prediction of surface roughness in turning

The effect of cutting speed and cutting tool geometry on machinability properties of nickel-base Inconel 718 super alloys

The effects of cutting speed and cutting tool geometry on cutting forces are investigated in this study. For this purpose, nickel-base super alloy, Inconel 718, is machined with dry cutting conditions by using digital controlled computer lathe with ceramic cutting tools in two different geometries and three different material qualities. Metal removing process is carried out for four different cutting speeds (150 m/min, 200 m/min, 250 m/min, and 300 m/min), while a cutting depth of 2 mm and a feed rate of 0.20 mm/rev are kept constant. As a result of the experiments, the lowest main cutting force, which depends on tool geometry, is obtained as 672 N with KYON 2100 SNGN 120712 ceramic tool and the maximum cutting force is determined as 1346 N with the ceramic cutting tool having KYON 4300 RNGN 120700 geometry. Depending on the cutting speed, the lowest main cutting force is recorded as 812 N at 250 m/min while the highest main cutting force is recorded as 955 N at 150 m/min. Plastic deformation, flank edge wear, notch and build-up edge are determined in high cutting speeds. © 2006 Elsevier Ltd. All rights reserved

ÇEKİ DEMİRİNDE SONLU ELEMANLARLA ELASTO-PLASTİK GERİLME ANALİZİ

Bu çalışmada çeki demirindeki gerilme analizi sonlu elemanlar metoduyla yapılmıştır. Sonlu eleman modelinin kurulmasında dört düğümlü izoparametrik elemanlar kullanılmış olup interpolasyon fonksiyonu olarak ise Lagrange polinomları alınmıştır. Eleman ağının oluşturulması için ayrı bir proğram yapılmış ve elemanlar otomatik olarak elde edilmiştir. Sonlu elemanlar için de özel bilgisayar proğramı geliştirilmiştir. Ele alınan çeki demirinde artık gerilmeleri hesaplayabilmek için elasto-plastik gerilme analizi yapılmıştır. Elasto plastik gerilme analizinde yüklemeler 400 daN'dan 1000 daN'a kadar 100 daN'luk artışlarla yüklenerek gerilme değerleri hesaplanmıştır. Bu analizde "Başlangıç gerilmesi metodu" kullanılmıştır