Yazar "Korkut, Volkan" seçeneğine göre listele

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    A Study on the Production of Riblet Patterns Providing Micro-scale Flow Control through FDM-type 3D Printers
    (2024) Korkut, Volkan; Akbıyık, Hürrem
    This study explores the Fused Deposition Modeling (FDM) additive manufacturing method as a practical alternative for flow characterization applications critical in aerospace technology. While there are significant studies in the literature on high-budget FDM devices for manufacturing high-dimensional consistency parts, research focusing on sub-millimeter riblet geometries using more accessible, practical, and flexible open-source devices remains limited. In this study, a printer that can be mechanically and programmatically modified was used to create parallel riblet patterns resembling wing structures on plates. Microscopic examinations and measurements were conducted on these riblets to address encountered issues. Observations revealed that hardware elements such as nozzle-table distance and nozzle circularity are crucial for homogeneous material extrusion. Additionally, it was observed that software-defined parameters like line width and flow rate significantly affect riblet dimensions. Particularly in experiments involving calibration of these parameters in open-source concept devices, riblet width, inter-riblet spacing, and riblet height were achieved with a high accuracy error rate of up to 1.83%, 1.33%, and 0.19%, respectively. Consequently, this study demonstrated the feasibility of producing riblets in this size and precision using widely available, cost-effective, and customizable FDM devices. Considering the significance of riblet structures in aerospace industries for flow control and surface modifications, this research aims to provide critical insights for the practical and effective production of more complex surface profiles in research and development activities.
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    Enhancing the tensile properties with minimal mass variation by revealing the effects of parameters in fused filament fabrication process
    (Springer Science and Business Media Deutschland GmbH, 2020) Korkut, Volkan; Yavuz, Hakan
    The Fused Filament Fabrication is a revolutionary method for the manufacturing industry. However, there are still numerous challenges need to be tackled in order to standardize the procedure of printing process. In this study, the process parameters of line width, shell thickness, infill orientation and infill overlap, have been experimentally investigated over their affect on tensile strength properties and the mass of the produced samples. Design of experiments has been planned, conducted and evaluated using the Taguchi approach. A total of 25 combinations of the four printing parameters with five different settings have been set according to the L25 Orthogonal Array table. The sample parts have been printed via widely used type low-cost and open-source 3D printer. Afterwards, the printed samples are tested for their tensile strength. The best combinations of the parameters with relevant settings have been revealed by S/N Ratio analysis. In order to validate the statistical results, the sample with newly found combination has been manufactured. Then, the ANOVA has been applied in order to reveal the percentage contributions of parameters to the tensile behaviour. It has been concluded that infill overlap and orientation parameters are dominant factors over the ultimate tensile strength of the samples. As a widespread effect, generalized equations have been established and presented in order to calculate the occupied area by an overlap. By implementing the equations, the users will be able to configure their input parameters in behalf of increasing the tensile strength while controlling the material consumption. © 2020, The Brazilian Society of Mechanical Sciences and Engineering.
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    Examining the Influential Parameters on Reducing both Energy and Time Requirements in Open-Source 3D Printers
    (2022) Korkut, Volkan
    The need for Fused Filament Fabrication (FFF) type 3D printers in additive manufacturing family is increasing day by day. In parallel to the accelerating developments in these devices, the technical difficulties and the cost of operation have started to decrease in time. There are numerous studies available in the way to enhance the mechanical properties of parts printed with these devices. However, the energy and the time management in the printing processes have also become a new focus of today's research for more eco-friendly operations. In this study, the amount of energy and the time consumed during the printing period are examined in detail. The experiments are planned in accordance with the Taguchi method for Design of Experiments. Signal-to-Noise Ratio and ANOVA analysis, which are widely accepted and powerful statistical tools in the field of experimental engineering, are used to interpret the results. It is observed that the parameters of platform temperature, the layer thickness, the printing speed and the nozzle temperature are the most influential process parameters on the required power and time respectively. The percentage contributions of these parameters to the process performance is also presented. Furthermore, the optimal combination of parameters with suitable levels were obtained in order to minimize both the power and the time requirement for printing processes. The statistical hypothesis are verified by the confirmatory experiments. As a result, the parameters that significantly reduce the amount of energy and processing time for the production of a part applicable to most printing processes are revealed.
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    Failure of surface modification 3D printed polymer materials by UV/ozone irradiation
    (Pergamon-Elsevier Science Ltd, 2023) Korkut, Volkan; Daricik, Fatih; Aktitiz, Ismail; Aydin, Kadir
    In today's technology, AM processes are widely adopted in the aerospace, energy, automotive, medicine, and agriculture industries. Fused Deposition Modeling (FDM) is one of the most remarkable methods in the AM family because of its superiorities. Besides the advantages pro-vided, the mechanical strength of the printed parts is still not at a satisfactory level. Here, there are various secondary processes applied to polymer materials to improve both the mechanical properties and functionality of the printed part. Among these processes, the UV/O3 surface treatment method stands out as the most suitable one in terms of ease of application. In this study, two different infill orientation angles were applied to two standard test models. The fabrication process was initiated using suitable process parameters for filaments made of Polylactic Acid (PLA) and Thermoplastic Polyurethane (TPU) materials. The purpose of this investigation was to examine the mechanical strength of 3D printed polymer structures. For the same purpose, the UV/O3 (UV/Ozone) process was applied to the manufactured samples. The samples are then subjected to tensile and compression tests, Shore surface hardness measurements and Scanning Electron Microscopy (SEM) analyze for both the evaluation of mechanical properties and the examination of fracture surface structures. Consequently, significant increases of 28.33%, 25.21%, 27.90%, and 32.92% were observed in material surface hardness levels. This study is important in terms of presenting that the mechanical properties of 3D printed parts can be significantly improved with UV/O3 application, which is an effective and a practical process.
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    In-Space Additive Manufacturing Based on Metal Droplet Generation Using Drop-on-Demand Technique
    (Springer, 2022) Korkut, Volkan; Yavuz, Hakan
    Metal-based droplet deposition technique is a promising method for obtaining 3D circuits and micro-sized conductive structures. Practically, direct part manufacturing can be achieved via droplet generator systems efficiently. In this study, micro-scale droplets are formed by a vibrated actuator. Furthermore, vibration stroke can be adjusted by means of a precise mechanical restrictor. The effects of the input ejection parameters are investigated over the droplet properties such as diameter, velocity and deposition conditions. The deposition morphologies with different layouts are first classified through theoretical equations. Experiments are then performed to obtain the predicted deposition patterns. As a result, it is observed that the vibration amplitude and voltage directly affect the flight velocity, diameter and wetting characteristic of the droplet, thus the deposition performance. In this context, it has been proven that droplets can be deposited in desired patterns when ejection parameters are properly configured. With such system, metallic structures can be obtained in non-laboratory environments such as space stations and aerospace vehicles those have limited access to the equipment. The presented device is designed to be modifiable, maintainable and compact structure. Given the freedom of design and flexibility in manufacturing, such devices become promising candidates for use in space environments involving different gravitational conditions.
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    Sustainable metal droplet formation via open-source, cost-effective, and modifiable droplet generator
    (Sage Publications Ltd, 2022) Korkut, Volkan; Yavuz, Hakan
    In this study, a metal droplet generator developed with an open-source concept is presented. The continuous droplet generation process was achieved without inert gas assistance. Owing to this desktop device, which is proposed as an alternative to high-cost metal printing devices, users can achieve stable droplets continuously at low costs. Taking into account the pressure balance inside the melting region, the necessary amount of a metal wire feed was first revealed. The droplets generated which are in good agreement with the theoretical calculations were then ejected via mechanically restricted vibrational impacts. The reproducibility of the system was also tested. The droplet formation stages were classified, and the stable parameter groups were revealed in accordance with the measurements. Moreover, the wire type material feeding issue in metal droplet generators, which were insufficiently studied so far, has also been examined. A dynamic feeder mechanism was introduced in detail. In conclusion, Ball Grid Array deposition and functional circuit printing have been successfully achieved. This study on a continuous metal droplet formation is also important for future studies because the structure of the device is easily accessible and modifiable.