Search

In this study; The effects of drawing speed (punch speed), sample width and punch diameter change on the Erichsen Index of Al 1050 (99.53% commercial purity) material, which is widely preferred in the industrial sector, were investigated experimentally. Fully automated Erichsen cupping equipment designed, manufactured and calibrated was used in the experimental studies. The tests were carried out with 8 mm, 15 mm and 20 mm spherical end punches in accordance with ISO 20482 standard at 5 mm/min, 6.25 mm/min and 8 mm/min punch speeds. From the results of the Erichsen cupping test; It has been determined that, from the point where the punch diameter reaches 1.5 times the value of the punch diameter, the punch load and the Erichsen Index-EI value decrease when the sample width is equal to the punch diameter. In addition, it was found that EI increased with increasing punch diameter. Experimental findings obtained from the test device designed, manufactured and calibrated; It has demonstrated that it is a hardware capable of detecting reliable Erichsen Index values with a precision of 0.01 mm., Bu çalışmada; endüstriyel sektörde tercih edilmesi yaygın olan AL1050 (%99,53 ticari saflıkta) malzemenin, çekme hızı (zımba hızı), numune eni ve zımba çapı değişiminin Erichsen Sabitine olan etkileri deneysel olarak incelenmiştir. Deneysel çalışmalarda tasarımı, imalatı ve kalibrasyonu yapılan tam otomasyonlu Erichsen şişirme donanımından faydalanılmıştır. Deneyler 5 mm/dakika, 6,25 mm/dakika ve 8 mm/dakika zımba hızlarında, TS EN ISO 20482 standardına uygun olarak 8 mm, 15 mm ve 20 mm küresel uçlu zımbalar ile yapılmıştır. Elde edilen Erichsen şişirme deneyi sonuçlarından; zımba çapının 1,5 katı değerine ulaştığı noktadan itibaren numune genişliğinin artmasıyla ve Erichsen Sabiti’nin düzenli artmaya başladığı, numune genişliği zımba çapına eşit olduğunda ise zımba yükünün ve Erichsen Sabiti değerinin düştüğü tespit edilmiştir. Ayrıca, zımba çapının artmasıyla Erichsen Sabitinin arttığı tespit edilmiştir. Tasarımı, analizi ve imalatı yapılan test cihazından elde edilen deneysel bulgular; 0,01 mm hassasiyette ve güvenilir Erichsen Sabiti değerlerini tespit edecek nitelikte bir donanım olduğunu göstermiştir.

In this study, drilling of AISI 4140 tempering steel with different gash rake angle the effects of the gash rake angle on the thrust force and drilling moment were investigated by experimental and FEM supported virtual simulation studies, and surface roughness was investigated experimentally.In the experiments, monolithic solid carbide drill are used that has +10 °, 0 °, -10 ° gash rake angle and diametre with 6,8mm. Experimental design was developed based on three different drill gash rake angle, cutting speed and feed rate with using Minitab 18 statistical software and Taguchi L9 experiment design method. Experiments have been carried out on AISI 4140 tempering steel is widely used in the manufacturing industry and can be purchased commercially. Variance Analysis (ANOVA) was applied to evaluate the test results and the effects of the independent variables (Ya: slit saw angle, Vc: cutting speed, f: feed amount) on the pushing force during hole drilling were evaluated according to significance value of 0.05. When the test results are examined, it is seen that the drill gash rake angle does not have a significant effect on the thrust force, drilling moment and surface roughness in drilling of AISI 4140 tempered steel, but it has a 63.78% effect on the thrust force. In the Finite Element supported virtual simulation studies, it is seen that it gives guiding results for the thrust force and drilling moment in drilling of AISI 4140 tempered steel with different drill slot swarf angles., Bu çalışmada farklı yarık talaş açısına (gash rake angle) sahip matkaplar ile AISI 4140 ıslah çeliğinin delinmesinde yarık talaş açısının itme kuvveti ve delme momenti üzerine etkileri deneysel ve FEM destekli sanal simülasyon çalışmaları ile yüzey pürüzlülüğü ise deneysel olarak araştırılmıştır. Deneylerde +10°, 0°, -10° yarık talaş açısına sahip 6,8 mm çapında yekpare karbür kaplamalı matkaplar kullanılmıştır. Deney tasarımı Minitab 18 istatistik yazılımı Taguchi L9 deney tasarımı kullanılarak üç farklı matkap yarık talaş açsı, kesme hızı ve ilerleme miktarı esas alınarak oluşturulmuştur. Deneyler imalat sanayisinde yaygın olarak kullanılan ve ticari olarak temin edilebilen AISI 4140 ıslah çeliği üzerinde gerçekleştirilmiştir. Deney sonuçlarını değerlendirmek amacıyla Varyans Analizi (ANOVA) uygulanmış olup bağımsız değişkenlerin (Ya: yarık talaş açısı, Vc: Kesme hız, f: İlerleme miktarı) delik deleme sırasında meydana gelen itme kuvveti üzerine etkileri 0,05 anlamlılık değerine göre değerlendirilmiştir. Deney sonuçları incelendiğinde AISI 4140 ıslah çeliğinin delinmesinde matkap yarık talaş açısının itme kuvveti, delme momenti ve yüzey pürüzlülüğü üzerinde üzerinde anlamlı bir etkisinin olmadığı görülse de itme kuvveti üzerinde %63,78’lik bir etkiye sahiptir. Yapılan Sonlu Elemanlar destekli sanal simülasyon çalışmalarında ise farklı matkap yarık talaş açılarıyla AISI 4140 ıslah çeliğinin delinmesinde itme kuvveti ve delme momenti için yol gösterici sonuçlar verdiği görülmektedir.

Bu çalışmada, havacılık sektöründe kompozit ve kompozit/metal istif yapılar üzerinde gerçekleştirilen ve montaj aşamasındaki tüm delme sürecini kapsayan manuel ve otomatik delik delme operasyonlarında matkap geometrisinin ve kesme hızının, delik kalitesi ve kesme performansına olan etkisi incelenmiştir. Çalışmalar dört aşamada gerçekleştirilmiştir. Faz-1 aşamasında ticari olarak elde edilebilen matkap geometrisi ile bu çalışma için geliştirilen üç yeni matkap geometrisi; delik çapı, silindiriklik ve delaminasyon verilerine göre deneysel olarak karşılaştırılmıştır. Faz-2 aşamasında, kompozit/metal istif plakada test edilmek üzere geliştirilen üç adet matkap geometrisi; delik çapı, yüzey pürüzlülüğü, delaminasyon ve takım aşınması verilerine göre deneysel olarak karşılaştırılmıştır. Faz-3A aşamasında, daha başarılı olduğu tespit edilen Tip-A matkap ile üç farklı kesme hızı değeri (51 m/dak, 94 m/dak, 163 m/dak); delik çapı, dairesellik, silindiriklik, ve yüzey pürüzlülüğü verilerine göre deneysel olarak karşılaştırılmıştır. Faz-3B aşamasında 94 m/dak kesme hızı ile delinen delikler; delik çapı, dairesellik, silindiriklik, yüzey pürüzlülüğü, takım aşınması ve delaminasyon verilerine göre deneysel olarak karşılaştırılmıştır. Deney sonuçları varyans analizi ve proses yeterlilik analizi kullanılarak değerlendirilmiştir. Çalışmalar montaj aşamasında kullanılan havalı portatif ekipmanlar ile tüm delik delme prosesini analiz edecek şekilde gerçekleştirilmiştir. Sonuç olarak, montaj aşamasında delik delme operasyonlarında matkap geometrisinin ve optimum kesme hızının belirlenmesinde farklı yaklaşımların deney sonuçları üzerindeki önemi ve etki oranları ortaya konmuştur. Faz-1 aşamasında yeni geliştirilen 17 nolu matkap geometrisinin, Faz-2 aşamasında Tip-A matkap geometrisinin, Faz-3A aşamasında 94 m/dak kesme hızının daha başarılı sonuçlar verdiği gözlenmiştir. Faz-1 aşamasındaki çalışma ile delik delme süresi delik başına 1,5 dakikadan 1 dakikaya düşürülmüştür. Faz-3B aşamasında delinen 30 adet delik sonuçlarına göre Tip-A matkap ve 94 m/dak kesme hızı için proses yeterlilik indisi değerlerinin 1,33 üzerinde çıktığı gözlenmiştir In this study, the effect of drill geometry and cutting speed on hole quality and cutting performance in manual and automatic drilling operations performed on composite and composite / metal stack structures by covering the entire drilling process during the assembly phase in the aviation industry was investigated. Studies were carried out in four stages. In Phase-1, three new drill geometries developed for this study and commercially available drill geometries were compared experimentally according to the hole diameter, cylindricity and delamination data. In Phase-2, three drill geometries developed for testing on composite / metal stack were compared experimentally according to the hole diameter, surface roughness, delamination and tool wear data. In Phase-3A, three different cutting speed values (51 m / min, 94 m / min, 163 m / min) by using Type-A drill were compared experimentally according to the hole diameter, circularity, cylindricity, and surface roughness data. In phase-3B, the holes drilled at 94 m / min cutting speed were compared experimentally according to the hole diameter, circularity, cylindricity, surface roughness, tool wear and delamination data. Experimental results were evaluated using variance analysis and process capability analysis. The studies were carried out to analyze the whole drilling process with pneumatic portable equipments used during the assembly operations. As a result, the importance and effect rates of different approaches on the test results in determining the drill geometry and optimum cutting speed in drilling operations during the assembly were revealed. It was observed that the newly developed drill geometry no 17 in Phase-1, Type-A drill geometry in Phase-2, cutting speed of 94 m / min in Phase-3A yielded more successful results. With the work in Phase-1, the drilling time has been reduced from 1.5 minutes per hole to 1 minute per hole. According to the results of 30 holes drilled in Phase-3B, it was observed that the process capability index values for Type-A drill and 94 m / min cutting speed were higher than 1,33.

Purpose: In this study, it is aimed to solve the problems which are work hardening, BUE, high cutting forces, low surface quality, and high tool wear, etc. encountered in machining owing to such properties of AISI 316L austenitic stainless steel such as high mechanical strength, ductility, and low thermal conductivity, using wave form end mills with variable rake and helix angle. Theory and Methods: First of all, cutting forces and surface roughness values were obtained with independent factor which are different processing parameters and different cutting tools. Secondly, these experimental findings were compared with variance and regression analyzes. Then, the optimum processing parameters for tool wear experiments were determined. Finally, the wear performance of the cutting tools was evaluated. Results: It is observed that higher cutting forces and lower surface quality compared to standard tools in wave form tools. The reason behind that could be the higher effects of disadvantages of the negative rake angle regions over the advantages of positive rake angle regions. In terms of tool wears, 6-550 (-4°, +12°) and 4-450 (-6°, +22°) tools with large positive and negative rake angles were shown higher tool wear behavior compared to the standard tool. However, 8-250 (-2°, +4°) and 8-650 (-3°, +4°) tools with smaller positive and negative rake angles were exhibited better wear behavior compared to the standard tool. Conclusion: As a result, in terms of the solution of high tool wear problem of AISI 316L stainless steel; it has been understood that it is suitable for rough machining especially since the 8-250 tool shows a lower wear rate of 17.2% compared to the standard tool. Also, this case will put the 8-250 tool in an advantages position in terms of cost/performance. Therefore, it has been determined that it is more appropriate to use standard tools in finishing (Table A). © 2021 Gazi Universitesi Muhendislik-Mimarlik. All rights reserved.

Controlling the amount of the cutting fluid used in machining processes is important in terms of its effects on the environment, human health, and also on the total cost of production. In this study, the AA7075 and AA2024 aluminum alloys were subjected to drilling process using four different cooling conditions (internal MQL, external MQL, conventional cooling and compressed air cooling), four different cutting speeds (100, 125, 150, 175 m/min) and four different feed rates (0.10, 0.15, 0.20, 0.25 mm/rev). At the end of experiments which have been performed with respect to Taguchi experimental design method, in addition to the hole quality such as surface roughness of hole, diametrical deviation, ovality and axial deviation, wear/build-up edge on cutting tools were investigated. The obtained data were evaluated by performing ANOVA and Signal/Noise (S/N) tests. At the end of experiments, it was determined that cooling method has the most effect on output parameters. It was observed that while the lowest values were found at conventional cooling application, the results from the application of internal MQL were very similar to conventional cooling method. While increased feed rate generally caused increase in all the output parameters, the cutting speed has unclear effect on the test results. The results of the hole quality obtained from the AA7075 alloy were found to be better than the results obtained from the AA2024 alloy, especially in poor cooling conditions such as compressed air cooling and external MQL application.

In this study, the effects of the cutting tool forms and cutting parameters on the surface integrity were experimentally investigated in machining of AISI 316L steel. In cutting tests, PVD coated MM and MF formed cutting tools and tool holder suitable for these cutting tools were used. Cutting parameters were determined by using three different feed rate, four different cutting speeds and two different depths of cut. The surface integrity was evaluated in terms of surface roughness, residual stress, microhardness and microstructure analysis. In all cutting conditions, it was observed that the surface integrity worsened when the depth of cut and feed rate increased, whereas the surface integrity improved when the cutting speed increased. When the cutting tool forms were compared, the best surface integrity results were obtained with the cutting tools which had MF form, while the worst surface integrity results were obtained by the cutting tools which had MM form. As rake angle increased, surface integrity improved. The worst surface integrity was obtained with the cutting speed 125 m/min, feed rate 0.3 mm/rev and depth of cut 2.5 mm, while the best surface integrity was obtained with the cutting speed 200 m/min, feed rate 0.1 mm/rev and depth of cut 1.25 mm.

Frezeleme, çok farklı şekilleri oluşturabilme ve yüksek üretim hızlarına ulaşabilme özelliklerinden dolayı en geniş ve yoğun kullanıma sahip talaşlı imalat operasyonlarından biridir. Günümüzde firmalar, işleme süresi ve kalitesini arttırabilmek adına özel kesici kenar tasarımına sahip frezeler kullanmaktadır. Bu çalışmada, helisel parmak frezenin kesici kenarları üzerine özel bir tasarıma sahip bir dalga formu verilerek tasarlanmış takımların standart parmak frezelere göre işleme performansının belirlenmesi ve karşılaştırılması amaçlanmıştır. Dalga formu sayesinde kesici kenar üzerinde -2° ila +10° derece arasında değişken ve kesici kenar boyunca devam eden bir talaş açısı oluşturulmuştur. Çalışmada, malzeme kalite özellikleri ile aynı olan standart ve değişken helis/değişken talaş açılı dalgalı forma sahip iki takımın işleme performansları, TS ISO 8688-2 standardı çerçevesinde, C45 (AISI 1045) çelik ve GG25 dökme demir referans malzemeler kullanılarak kıyaslanmıştır. Deneysel analiz sonuçlarına göre değişken talaş açısı ile kesici kenar mukavemetinin artması, kesme kararlılığının artması ve dolayısı ile takım performansının artması sağlanmıştır Milling is one of the most extensive and intensive machining operations due to its ability to form very different shapes and achieve high production speeds. Nowadays, companies use end mills with special cutting edge design in order to increase processing time and quality. In this study, it is aimed to determine and compare the machining performance of the tools designed by giving a special waveform on cutting edges of helical end mill in accordance with standard end mill. Under favor of to the waveform, rake angle is formed on the cutting edge that varies between -2° and +10°degrees and runs along the cutting edge. In this study, the machining performances of two tools having the same standard and variable helical / variable rake angle waveform which are the same as the material quality characteristics are compared using C45 (AISI 1045) steel and GG25 cast iron reference materials according to TS ISO 8688-2 standard. According to experimental analysis results, increased cutting edge strength with a variable rake angle, the cutting is achieved increased stability and thereby increased tool performance

Nowadays, weight reducing is become possible with composite materials taking place of steel (60-80%) and aluminum (20-50%). Composite materials have become the preferred materials for many engineering applications. However, besides the advantages of composite materials, there are problems in manufacturing. Manufacturing of fiber reinforced composite materials are more difficult than other materials. This situation needs to be very selective in terms of cutting tools. In this study, a unique PCD cutting tool design was devised which is capable of eliminating the encountered difficulties, especially the exfoliation (delamination) problem on laminated/laminar formed composite board during machining carbon fiber reinforced composite (CFRC) materials. With this cutting tools delamination and cutting forces investigated on milling of CFRP materials. 350, 400, 450 m/min cutting speeds and 1270 mm/min constant feed rate were selected as cutting parameters. The first tool were showed the best performance in consequence of the tests. Increasing cutting speed influences the and cutting forces posivitely. Besides, the effective parameters on delamination and cutting forces, were determined according to the obtained ANOVA statistics after the regression analysis.

Assessment of performance criteria through experimental study is fairly costly and time-consuming. Therefore finite elements based simulation software is used instead of costly and time-consuming experimental work. In this paper, a performance assessment was carried out when drilling GGG50 spheroidal graphite cast iron using 4 different drill geometries. The experimental studies were verified by means of finite elements based analysis method. Deform 3D software was used to simulate chip formation process and predict outputs such as forces, cutting temperature and chip morphology. In order to examine the influence of drill geometries on the process outputs, 4 different drill geometries were used. In order to predict the thrust forces, temperature distribution and the chip form, a series of solutions were employed. A good agreement was seen between the experimental results and finite element analysis results for the thrust force and chip form