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Warm hydromechanical deep drawing process is an innovative manufacturing technology that offers considerable increase in the formability of the materials. However, the weakness of the process lies in its complexity. For a successful process, the optimum temperature distribution of the material must be achieved. In addition, optimum loading profiles (pressure of fluid and force of blank holder) should be applied according to the punch position. These conditions can most easily be determined with the proven finite element analysis (FEA). In this study, the effect of the temperature variability of the tools on the results of the FEA was investigated. Namely, the study aims at investigating whether the temperature variability of the tools needs to be modeled or not in FE analysis. For a simple and fast analysis, it is generally accepted that the tools have a homogeneous temperature distribution and the temperature is constant throughout the process. However, in the experiments in this study, the temperatures of the tools changed considerably. The temperature variability of the tools was first measured in the experiments and then modeled in the FEA. In the analysis performed for the AA 5754 aluminum alloy, the thickness distribution of the deep drawn part was compared with the results of an FEA performed at a constant and same temperature condition. Results in both conditions were very close to each other and indicated that there is no need to obtain and model the temperature distribution or temperature variability of the tools throughout the process. It was possible to perform the FEA with acceptable accuracy by assuming a constant and homogeneous temperature distribution in the tools throughout the process.

In this paper, an improved approach is proposed to determine the optimal profiles of two controllable process parameters (hydraulic pressure and blank holder force), which improve the forming condition and/or make better use of forming limits in hydromechanical deep drawing (HMD) process. A method based on adaptive finite element analysis coupled with fuzzy control algorithm (aFEA-FCA) was developed using LS-DYNA to determine the optimal loading profiles and thus to maximize the limiting drawing ratio (LDR). Maximum thickness reduction, maximum wrinkle height in the flange region of the sheet metal blank, and position of the nodes in the unsupported portion of the sheet metal blank between punch and die were used as criteria in the fuzzy control algorithm. Different rule-based matrices were compared by considering the maximum thinning occurred in the sheet metal blank, and thus, the most accurate matrices were determined for the control algorithm. The optimal loading profiles could be determined in a single FEA, thus reducing the computation time. The proposed approach enables determining the optimal loading profiles and also could be applied to complex parts easily. In addition, effects of initial blank diameter and coefficient of friction between the sheet-blank holder and sheet-die on the optimal loading profiles were investigated. An attainable LDR of 2.75 for AA 5754-O sheet material in hydromechanical deep drawing process was proven experimentally using the optimal loading profiles determined by adaptive FEA.

Adaptive neural-network based fuzzy logic inference system (ANFIS) is a useful method instead of costly Finite Element Analysis (FEA) in order to reduce investigation cost of forming processes. In this research, the effect of hydromechanical deep drawing (HDD) process parameters on AA5754-O sheet was investigated by FE simulations with analysis of variance (ANOVA) and Adaptive Neuro-Fuzzy Modeling approach. In order to determine the prediction error of the ANFIS model according to FEA, firstly a series of FEA of the HDD process were conducted according to Taguchi's Design of Experiment Method (DOE). The results of the FEA were confirmed by comparing the thickness distributions of the formed cups by experimentally and numerically. Moreover an adaptive neural-network based fuzzy logic inference system (ANFIS) was created according to results of simulation to predict the maximum thinning of AA5754-O sheet without needing FE simulations. The calculation performances of the ANFIS model were determined by comparing the estimated results with the results of the FE simulations. By using the results of the FE simulations which were conducted according to a matrix plan, the effects of the parameters to the thinning of the blank were determined by the analysis of variance (ANOVA) method. ABAQUS and MATLAB/ANFIS/Simulink softwares were used to realize and simulate proposed techniques. Mean error of prediction result of ANFIS is found as 0.89% according to FEA.

In this research, the body of a sheet hydroforming press, which can produce an industrial product, was designed and dimensioned. Initially, the required pressure and forces to produce the industrial product were determined by finite element analysis. Then, structural analysis of the press body was conducted by using these forces in Solidworks Premium simulation module. The strain gauges were bonded on various critical areas of the press body. The strains were measured for various loading conditions and compared with the analysis results. According to the results obtained, the strain values obtained from the analysis and measured experimentally are in good agreement with each other.

Warm sheet hydroforming process has being investigated in recent years with its high formability feature. Warm hydromechanical deep drawing (WHDD) which is a type of the warm sheet hydroforming process is important for deeper parts. To determine the formability of the WHDD process the most convenient tool is Limiting Drawing Ratio (LDR). But determination of the LDR accurately needs using of the most convenient tool dimensions. In this study optimal geometrical parameters were investigated by FE Analyses of the process. Consequently optimum punch and die diameters and optimum punch nose and die entrance radiuses were determined for accurate LDR value.

Aluminum alloys have limited usage because of their limited formability at room temperatures. In order to design and develop more parts made of aluminum, new forming techniques such as hydroforming, warm forming and warm hydroforming have been researched to overcome the low formability issues. This, in turn, necessitates understanding and modeling the behavior of aluminum alloys at different temperatures and strain rates. This paper deals with the investigation of the effect of temperature and strain rate sensitivity on the formability of AA 5754 aluminum alloy. Tensile tests were carried out at temperatures of 20,100,180 and 260°C and forming rates of 25, 100 and 250 mm/min. The mechanical properties and flow curves were obtained and the strain rate sensitivities were calculated at different strains and temperatures. The effects of temperature and strain rate sensitivity on the formability were introduced.

The objective of this experimental study is to determine electrical discharge machining (EDM) parameters that offer the best adhesion at the interface of a machined titanium–porcelain composite. First of all, with Taguchi method, machining parameters that will be effective in the bonding strength as well as their interactions on each other were determined in the test. Then, multiple level experiments were conducted to determine how the effective parameters varied over a wide area. Slopes of the curves obtained in these tests were studied, and then, final tests were conducted to obtain the best bonding strength possible. In this way, machining parameters that would offer the highest bonding strength of the titanium–porcelain matrix in a stepwise adjustable EDM machine were obtained. By taking into consideration the steps on the EDM machine where the tests were conducted, it is seen that, when a full factorial experiment is undertaken, 5 power × 2 polarity × 2 type of dielectric × 2 sandblasting or non-sandblasting × 2 kind of electrode × 10 pulse-on time, it necessitates 800 different tests to be executed, but, with the applied method, 16 + 18 + 3 yields 37 different tests where the results that include all possible alternatives were obtained. As a result, EDM machining parameters that offer the highest adhesion and are relatively higher, 31.5 N/mm2, than the acceptable minimum value of 25 N/mm2 were specified.

Reduced machining time and increased accuracy for a sculptured surface are both very important when producing complicated parts, so, the step-size and tool-path interval are essential components in high-speed and high-resolution machining. If they are too small, the machining time will increase, whereas if they are too large, rough surfaces will result. In particular, the machining time, which is a key factor in high-speed machining, is affected by the tool-path interval more than the step size. The present paper introduces a ‘system software’ developed to reduce machining time and increased accuracy for a sculptured surface with Non-Uniform Rational B-Spline (NURBS) patches. The system is mainly based on a new and a powerful artificial intelligence (AI) tool, called artificial immune systems (AIS). It is implemented using C programming language on a PC. It can be used as stand alone system or as the integrated module of a CNC machine tool. With the use of AIS, the impact and power of AI techniques have been reflected on the performance of the tool path optimization system. The methodology of the developed tool path optimization system is illustrated with practical examples in this paper.

Electrical discharge machining (EDM) is a non-traditional production method that has been widely used in the production of dies throughout the world in recent years. The most important performance measure in EDM is the surface roughness; among other measures material removal and tool wear rates could be listed. In this study, experiments were performed to determine parameters effecting surface roughness. The data obtained for performance measures have been analyzed using the design of experiments methods. A considerably profound equation is obtained for the surface roughness using power, pulse time, and spark time parameters. The results are discussed.

WOS: 000322326300060, In this study, the effects of sheet thickness and anisotropy of AA2024-T4 on forming limit curve (FLC) are experimentally investigated according to ISO 12004-2 standard. A new limit strain measurement method is proposed by using the grid analysis method so as to determine limit strains conveniently and reliably. In addition to the regular test specimens, various widths are added to enhance the FLC's accuracy at the plane strain condition (PSC). The accuracy and reliability of the proposed method are verified for different materials. Results illustrate that an increase in the sheet thickness increases the FLC level. The additional experiments for additional widths improve the accuracy of the FLC at the PSC, and the position of the lowest major strain value differs from the literature. However, the effect of anisotropy on the FLC is found to be insignificant. Finally, experimental and numerical case studies are carried out for conventional deep drawing, stretch drawing, and hydraulic bulge processes. Results reveal that different FLCs are necessary for different thicknesses for accurate predictions., Scientific and Technological Research Council of Turkey (TUBITAK) [108M516]; Research Project Office (BAP) of Necmettin Erbakan University; Research Project Office (BAP) of Selcuk University, This work was supported by The Scientific and Technological Research Council of Turkey (TUBITAK; Grant number 108M516). It was also supported by the Research Project Offices (BAP) of Necmettin Erbakan and Selcuk Universities. TUBITAK, The Research Project Offices, Metal Forming Laboratory at the Nigde University, and Metal Forming Center of Excellence at the Atilim University are profoundly acknowledged. This work has been extracted from Murat Dilmec's PhD thesis.

Bu çalışmada kütlesel özel üretim, özel protez tasarımları gibi yeni ürün konfigurasyonlarının tasarımını tasarım parametrelerinin değiştirilmesi ile hızlı ve kolayca sağlayan parametrik tasarım felsefesi üzerinde durulmuştur.Parametrik tasarımda temel teşkil eden kısıtlılık kavramı örneklerle açıklanmıştır. Dizayn tablosu ve Excel VBA araçları kullanılarak geliştirilen bir parametrik tasarım örneği, Excel sayfaları, program arayüzleri ve akış şeması de tanıtılmıştır Geliştirilen programla yatağa gelen eksenel ve radyal kuvvetlerin, devir sayısı ve rulman ömrü gibi kısıtların girilmesi ile, sabit rulmanlı yatak tablolarından rulmanlı yatak boyutları elde edilerek, çeşitli konstrüksiyonlarda kullanılabilecek sabit rulmanlı yatakların katı modelleri oluşturulabilmektedir., This study focuses on parametric design philosophy, which enables fast and easy design of new product configurations such as special mass production, special prostheses designs, by simply changing the design parameters Constraint, the basic concept of parametric design, has been explained by way of examples A parametric design example, developed by a design table and Excel VBA tools, has been presented with Excel worksheets, program Interfaces and flowcharts The developed program gets constraint inputs such as axial and radial forces acting on the beanng, number of revolutions and lifetime of the roller and calculates the dimensions of the roller bearing using the fixed roller beanng charts Finally, the program outputs solid models of the roller bearings that may be used in various constructions.

WOS: 000315009100002, In this study, experimental studies were conducted to evaluate the differences between the ASTM E2218-02 and ISO 12004-2 standards that are used for construction of the forming limit curve (FLC) and that made various assumptions, which create dissimilar FLCs for the same material. The comparison was made for two materials which have moderate brittle and ductile characteristics, AA2024-T4 and AA5754-O alloys, respectively. The effects of a specimen's geometry, lubrication condition, and determination methods of limit strains on FLCs were considered and compared. Because the same strain evaluation method should be used for the standards, so as to be able to investigate the effect of only standards, a simple method in the computer grid analysis system was used. To test the validity and the reliability of the method, limit strains on the same specimens were also determined with using a real-time measurement method for the ISO experiments, and the results reveal that the method is reliable. Failure mechanisms were inspected for further investigation. The Nakajima specimens formed with the two standards showed different failure mechanisms. Finally, conducting the case studies, it was concluded that ISO 12004-2 yields more reliable and reproducible results than the ASTM standard., Scientific and Technological Research Council of Turkey (TUBITAK) [108M516]; Research Project Unit (BAP) of Selcuk University [09101005], This work is supported by The Scientific and Technological Research Council of Turkey (TUBITAK), Project No. 108M516, Project Title: "Adding Drawbead to the Blank Holder for Enhancing Formability of Aluminum Alloy Sheets with Hydroforming Process." This work is also supported by the Research Project Unit (BAP) of Selcuk University under Project No. 09101005. TUBITAK, Selcuk University, and Metal Forming Laboratory in Nigde University, and Metal Forming Center of Excellence in Atilim University are profoundly acknowledged.