Researcher:
Yiğit, İsmail Enes

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İsmail Enes

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Yiğit

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Yiğit, İsmail Enes

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2015 - 201942020 - 20225

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Researcher Of Publications: search.filters.isAuthorOfPublication.acd12410-7bfe-45cd-a0c1-1a2ca55879b1

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Now showing 1 - 9 of 9
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    Analysis of tool orientation for 5-axis ball-end milling of flexible parts
    (Elsevier, 2015) N/A; N/A; Department of Mechanical Engineering; Khavidaki, Sayed Ehsan Layegh; Yiğit, İsmail Enes; Lazoğlu, İsmail; PHD Student; PhD Student; Faculty Member; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 179391
    This article investigates the effects of lead and tilt angles in 5-axis ball-end milling of flexible freeform aerospace parts by considering process mechanics. In current CAM technology, tool posture is determined by geometrical analysis only. However, in high-performance 5-axis milling, not only the geometry, but also the mechanics of the process is critical. Therefore, a new and comprehensive mechanics-based strategy is proposed for selection of tool postures considering process parameters such as cutting force, torque, part vibration, and surface quality. Effectiveness of the proposed strategy is validated by conducting experiments on 5-axis ball-end milling of flexible freeform structures. (C) 2015 CIRP.
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    Robotic additive turning with a novel cylindrical slicing method
    (Springer London Ltd, 2022) N/A; N/A; Department of Mechanical Engineering; Yiğit, İsmail Enes; Khan, Shaheryar Atta; Lazoğlu, İsmail; Phd Student; PhD Student; Faculty Member; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 179391
    The turning process used from ancient times to today's modern turning centers is based on material removal. This article presents a new work to integrate additive manufacturing into the turning process and generate complex free-form additive turning part geometries. The conventional slicing method used in AM is the planar slicing method. In the planar slicing method, the computer-aided design (CAD) model is sliced using planes, and as a result, two-dimensional toolpaths are formed. A new slicing method is required to achieve additive turning parts. This work proposes a generalized, cylindrical slicing method that generates nonplanar toolpaths wrapped around a cylinder. The model is sliced by cylindrical layers, with increasing radii at each layer. As a result, three-dimensional toolpaths that are suitable for additive turning are generated. In conventional AM, lower tensile strength is observed in the build orientation of the part where the layers bind. Additive turning increases the low tensile strength observed in conventional AM. Additionally, it reduces and, at times, even eliminates the support structures required for certain CAD models. The cylindrical slicing results are verified by additively turning different CAD models using a six-axis robotic serial manipulator fitted with a fused filament fabrication end effector and an external turning axis. Tensile tests are conducted on conventional AM and additive turning models to verify the improvement in tensile strength.
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    Helical slicing method for material extrusion-based robotic additive manufacturing
    (Springer, 2019) N/A; Department of Mechanical Engineering; Yiğit, İsmail Enes; Lazoğlu, İsmail; Phd Student; Faculty Member; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 179391
    The purpose of this article is to introduce a nonplanar helical slicing method for additive manufacturing (AM) which forms a single continuous three-dimensional tool path and removes seam defects. In the proposed method, the geometry is initially sliced into planar slices. Afterwards, using two consecutive planar slices, direction vectors from the current layer to the next layer are constructed. These vectors are used to generate helical slices in-between planar slices. Repeating the process for all the planar slices results in a single helical sliced tool path. With the direction vectors, geometric improvements over the existing spiralization methods are obtained. With the helical slicing method, the seam defects which are found in the extrusion start–stop points of the planar slices are removed. The switching control of the extruder is simplified, and non-extrusion movements of the extruder are eliminated. The generated tool path is tested using a material extrusion-based robotic AM setup. Manufactured models are investigated in detail under the scanning electron microscope. The method is applicable for additively manufacturing complex freeform shell type, genus zero models with no infill and minor overhangs. This helical slicing method removes the form errors found in those of previously developed solutions.
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    Additive manufacturing with modular support structures
    (The University of Texas at Austin, 2020) Department of Mechanical Engineering; Department of Mechanical Engineering; N/A; Lazoğlu, İsmail; Isa, Mohammed A.; Yiğit, İsmail Enes; Faculty Member; Researcher; Phd Student; Department of Mechanical Engineering; College of Engineering; College of Engineering; Graduate School of Sciences and Engineering; 179391; N/A; N/A
    Additive manufacturing is praised to have low material waste compared to conventional subtractive manufacturing methods. This is not always the case when the computer aided design (CAD) model consists of large overhangs. In such cases, fabrication of support structures are required to fill the space between the CAD model and the manufacturing bed. In post processing, these support structures must be removed from the model. These supports become waste and reduce the buy-to-fly ratio. In this paper, we present a pre-fabricated reusable modular support structure system which minimizes the fabrication of conventional support structures. The conventional supports are replaced with modular support blocks wherever possible. The blocks are stacked under the overhang with a robot arm until the overhang of the model is reached. Conventional supports can be fabricated on top when needed with fused filament fabrication. This strategy reduces fabrication of conventional supports. Thus, faster fabrication times are obtained with higher buy-to-fly ratios.
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    Analysis of build direction in deposition-based additive manufacturing of overhang structures
    (The University of Texas at Austin, 2020) Department of Mechanical Engineering; Department of Mechanical Engineering; N/A; Lazoğlu, İsmail; Isa, Mohammed A.; Yiğit, İsmail Enes; Faculty Member; Researcher; Phd Student; Department of Mechanical Engineering; College of Engineering; College of Engineering; Graduate School of Sciences and Engineering; 179391; N/A; N/A
    Additive manufacturing (AM) has gained repute as a direct method of fabrication of complex parts. However, the requirement for each layer to be structurally supported can make parts with overhangs hard to produce without alterations to the parts. This work proposes using multi-axis additive manufacturing to fabricate and analyze freeform overhangs such as bridge structures. Multi-axis AM allows reorientation of the build direction so that overhangs can be 3D printed. Consequently, decision on the build orientation is necessary and its result should be analyzed. The effect of the AM build direction with respect to the overhang's local surface directions will be studied. A Rhinoceros® plugin is designed to generate the path of the multi-axis AM for the unsupported components like roofs, bridges and protrusions. The effects of the build direction on the surface quality and deformation of the components are studied.
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    Mechanics of milling 48-2-2 gamma titanium aluminide
    (Elsevier, 2020) Layegen, S. Ehsan; Arrazola, Pedro-J.; Lazcano, Xabier; Aristimuno, Patxi-X.; Subaşı, Ömer; Yavaş, Çağlar; N/A; Department of Mechanical Engineering; N/A; N/A; Hussain, Abbas; Lazoğlu, İsmail; Yiğit, İsmail Enes; Öztürk, Çağlar; PhD Student; Faculty Member; PhD Student; PhD Student; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; College of Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; N/A; N/A; 179391; N/A
    Accurate and fast prediction of cutting forces is important in high-performance cutting in the aerospace industry. Gamma titanium aluminide (gamma-TiAl) is a material of choice for aerospace and automotive applications due to its superior thermo-mechanical properties. Nevertheless, it is a difficult to machine material. This article presents the prediction of cutting forces for Ti-48Al-2Cr-2Nb (48-2-2) gamma-TiAl in milling process using orthogonal to oblique transformation technique. The novelty of this paper lies in reporting the orthogonal database of 48-2-2 gamma-TiAl. Fundamental cutting parameters such as shear stress, friction angle and shear angle are calculated based on experimental measurements. Friction coefficients are identified for two different coating conditions which are AlTiN, and AlCrN on carbide tools. Predicted results are validated with the experimental cutting forces during end milling and ball-end milling operations for different cutting conditions. The simulated results showed good agreement with the experimental results, which confirms the validity of the force model.
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    Spherical slicing method and its application on robotic additive manufacturing
    (Springer Nature, 2020) Department of Mechanical Engineering; N/A; Lazoğlu, İsmail; Yiğit, İsmail Enes; Faculty Member; Phd Student; Department of Mechanical Engineering; College of Engineering; Graduate School of Sciences and Engineering; 179391; N/A
    This article presents a spherical slicing method for additive manufacturing (AM) which is used to lay additive layers on a spherical surface, thus removing the stair stepping effect, increasing structural integrity and tensile strength. A toolpath is required to guide the extruder in the three-dimensional space and deposit the material in the desired locations. These tool paths are computed using slicing algorithms. The well-established method in AM industry is the planar slicing. In this method, the Computer Aided Design model is sliced using planes and as a result, two-dimensional tool paths are formed. With the introduction of multi-axis AM machines, development of new non-planar slicing algorithms has started. In this article, a novel non-planar, spherical slicing, is introduced. In the proposed spherical slicing method, the model is sliced by spherical shells such as that of an onion. These spherical slices are then used to generate the appropriate tool paths for guiding the robotic manipulator in three-dimensional space together with the corresponding orientation to lay the spherical layers on top of the previously manufactured planar base. Results are verified by manufacturing a model using a six-axis robotic serial manipulator by fused deposition modeling.
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    PublicationOpen Access
    A solid modeler based engagement model for 5-axis ball end milling
    (Elsevier, 2015) Department of Mechanical Engineering; Yiğit, İsmail Enes; Khavidaki, Sayed Ehsan Layegh; Lazoğlu, İsmail; Faculty Member; Department of Mechanical Engineering; Manufacturing and Automation Research Center (MARC); Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 179391
    5-axis sculptured surface milling is a difficult machining process to model due to the complex geometrical engagement between the workpiece and the cutter. Due to the complexity of the process, the engagement cannot be found analytically with conventional methods. Therefore, solid modeler based simulations are utilized to compute the engagement map. This paper presents a comprehensive and efficient strategy for engagement modeling of ball end milling using a solid modeler kernel, namely Parasolid. Accuracy of the model is validated by simulating the cutting forces based on the calculated engagements and compare it with experimentally measured cutting forces. (C) 2015 The Authors. Published by Elsevier B. V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
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    PublicationOpen Access
    Dynamic build bed for additive manufacturing
    (The University of Texas at Austin, 2019) Department of Mechanical Engineering; Yiğit, İsmail Enes; Lazoğlu, İsmail; Faculty Member; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 179391
    Compared to subtractive manufacturing, additive manufacturing generally has low material waste. However, models with large overhangs require manufacturing of support structures which ends up as waste material. This paper proposes the use of a dynamic build bed for reducing support structures. The bed consists of an array of actuated pins which move in the build orientation. Each pin can be individually moved to the correct height for supporting the given model. Two separate applications of the build bed are investigated. In the first application, the dynamic build bed is used as support structures in deposition-based AM methods. The pins individually raise out of the build bed to support the overhang geometry at the given deposition height. The second application is in powder-based AM methods. In the second application, the pins are used to fill the space of the powder where the geometry will not occupy. The pins are individually lowered in the build orientation to make space for a new powder layer. Thus, saving excessive deposition of powder.