Researcher:
Khavidaki, Sayed Ehsan Layegh

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PhD Student

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Sayed Ehsan Layegh

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Khavidaki

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Khavidaki, Sayed Ehsan Layegh

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2012 - 201711

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Now showing 1 - 10 of 11
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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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    Instantaneous tool deflection model for micro milling
    (Springer London Ltd, 2015) N/A; N/A; N/A; Department of Mechanical Engineering; Mamedov, Ali; Khavidaki, Sayed Ehsan Layegh; Lazoğlu, İsmail; Researcher; PhD Student; Faculty Member; Department of Mechanical Engineering; Manufacturing and Automation Research Center (MARC); N/A; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 179391
    This paper investigates modeling of machining forces with shearing and plowing mechanisms and estimates instantaneous tool deflections in micro end milling. Cutting forces directly affect cutter deflection, which will influence the quality of machined surfaces. Thus, it is important to model cutting forces in order to avoid imperfections in a final manufactured part. Force analysis is also essential for modeling of mechanics and dynamics of micro end milling. The proposed force model considers plowing phenomena of micro milling process and calculates it from elastic recovery of plowed workpiece material. The force distribution on the micro end mill is calculated by a mathematical model. Tool deflections during the cutting process result in final part imperfections. Therefore, it is important to predict instantaneous tool deflections in order to manufacture accurate parts and to avoid premature tool failure. Presented deflection and force models are validated on titanium alloy Ti-6Al-4V grade 5, through micro end milling experiments for a wide range of cutting conditions using laser displacement sensors and mini dynamometer.
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    High performance 5-axis milling of complex sculptured surfaces
    (Springer-Verlag London Ltd, 2012) Erdim, Huseyin; Department of Mechanical Engineering; N/A; N/A; Lazoğlu, İsmail; Boz, Yaman; Khavidaki, Sayed Ehsan Layegh; Faculty Member; Master Student; PhD Student; Department of Mechanical Engineering; College of Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; 179391; N/A; N/A
    Five-axis milling processes are used widely in various industries such as aerospace, die-mold and biomedical industries where surface quality and integrity is important and the production tolerances are very tight. Therefore, improving surface quality and integrity without sacrificing productivity is crucial in these industries. Improvements in CAD/CAM, cutting tool and the machine tool technologies allow the production of high precision parts with less cycle times. In order to obtain desired quality and productivity, process parameters such as feedrate, spindle speed, axial and radial depth of cut have to be selected appropriately. Most of the time, selection criterion is based on engineering expertise or trial and error methods. Besides, to prevent the cutter or the machine to be damaged, machining parameters are selected conservatively, and therefore, virtual machining simulation for milling processes is an increasing demand before the production of the free-form surfaces.
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    Feedrate optimization for freeform milling considering constraints from the feed drive system and process mechanics
    (Elsevier, 2013) Erkorkmaz, Kaan; Erdim, Hüseyin; Department of Mechanical Engineering; Khavidaki, Sayed Ehsan Layegh; Lazoğlu, İsmail; N/A; Faculty Member; Department of Mechanical Engineering; Manufacturing and Automation Research Center (MARC); College of Engineering; N/A; 179391
    This paper presents a new and comprehensive strategy for planning minimum cycle time tool trajectories subject to both machining process related constraints, and also limitations of the feed drive control system. The machining process is considered by computing the workpiece-tool engagement along the toolpath and setting local feed limits to maintain a specified resultant cutting force. The drive constraints are considered by limiting the velocity, acceleration, and jerk magnitudes commanded to each actuator. Feed profiling is realized with uninterrupted acceleration transitions, capable of spanning multiple toolpath segments. Effectiveness of the proposed strategy is demonstrated in sculptured surface machining experiments. (C) 2013 CIRP.
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    Mechanics of titanium machining
    (Springer-Verlag Berlin, 2014) N/A; Department of Mechanical Engineering; N/A; Department of Mechanical Engineering; Lazoğlu, İsmail; Khavidaki, Sayed Ehsan Layegh; Mamedov, Ali; Faculty Member; PhD Student; Researcher; Department of Mechanical Engineering; Manufacturing and Automation Research Center (MARC); College of Engineering; Graduate School of Sciences and Engineering; College of Engineering; 179391; N/A; N/A
    Titanium is widely used material in advanced industrial applications such as in aeronautics and power generation systems because of the distinguished properties such as high strength and corrosion resistance at elevated temperatures. On the other hand, the machinability of this material is poor. Relatively low thermal conductivity of Titanium contributes to rapid tool wear, and as a result, high amounts of consumable costs occur in production. Therefore, understanding the mechanics of titanium machining via mathematical modeling and using the models in process optimization are very important when machining Titanium both in macro and micro scales. In this chapter, mechanical effect of process parameters in five axis milling and micro milling are analyzed. Thus, different cutting conditions were tested in dry conditions and the effects of tool orientation on cutting forces in five axis macro milling was investigated. For five-axis ball end milling operation, a series of experiments with constant removal rate and different tool orientation ( different lead and tilt angle) were conducted to investigate the effect of tool orientation on cutting forces. The aim of the tests was finding the optimum orientation of the cutter in which the normal cutting force applying on machined surface is minimum. Moreover, a new method to predict cutting forces for micro ball end mill is presented. The model is validated through sets of experiments for different engagement angles. The experiment and the simulation indicated that the tool orientation has a critical effect on the resultant cutting force and the component that is normal to the machined surface. It also possible to predict the tool orientation in which the cutting torque and dissipated energy is minimum. In micro milling case, the force model for ball end mill is able to estimate the cutting forces for different cutting conditions with an acceptable accuracy.
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    3D surface topography analysis in 5-axis ball-end milling
    (Elsevier, 2017) N/A; Department of Mechanical Engineering; Khavidaki, Sayed Ehsan Layegh; Lazoğlu, İsmail; PHD Student; Faculty Member; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 179391
    This article presents a new analytical model to predict the topography and roughness of the machined surface in 5-axis ball-end milling operation for the first time. The model is able to predict the surface topography and profile roughness parameters such as 3D average roughness (Sa) and 3D root mean square roughness (Sq) by considering the process parameters such as the feedrate, number of flutes, step over and depth of cut as well as the effects of eccentricity and tool runout in 5-axis ball-end milling. This model allows to simulate the effects of the lead and tilt angles on the machined surface quality in the virtual environment prior to the costly 5-axis machining operations. The effectiveness of the introduced surface topography prediction model is validated experimentally by conducting 5-axis ball-end milling tests in various cutting conditions. (C) 2017 Published by Elsevier Ltd on behalf of CIRP.
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    PublicationOpen Access
    Offline force control and feedrate scheduling for complex free form surfaces in 5-Axis milling
    (Elsevier, 2012) Erdim, Hüseyin; Department of Mechanical Engineering; Khavidaki, Sayed Ehsan Layegh; Lazoğlu, İsmail; Faculty Member; Department of Mechanical Engineering; Manufacturing and Automation Research Center (MARC); College of Sciences; N/A; 179391
    An enhanced Force model based Feedrate Scheduling (FFS) technique for rough cutting of parts with complex free form surfaces in 5-axis machining is presented. In order to estimate the cutting forces in complex 5-axis machining an enhanced solid modeler kernel based model is developed to find the complicated engagement between cutter and workpiece for each cutter location. In this paper, cutter-workpiece engagement model is presented using the commercial Parasolid solid modeler kernel, and then cutting forces are estimated based on the developed model. In this approach, the resultant cutting forces are kept constant on a user defined threshold. The feedrate will be adjusted to keep the resultant cutting forces constant all along the tool path. Therefore, it is shown that this approach allows decreasing the cycling time drastically. The scheduled feedrate in each cutter location is carried out in NC blocks using an off-line postprocessor that can be used in commercial CAM software. Eventually, the proposed FFS technique is experimentally tested on rough machining of an impeller with free form surfaces and force validations are presented in this article.
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    PublicationOpen Access
    Friction coefficients on surface finish of AlTiN coated tools in the milling of Ti6Al4V
    (Elsevier, 2017) Akgun, Ali; Yavas, Caglar; Department of Mechanical Engineering; Akmal, Mohammad; Khavidaki, Sayed Ehsan Layegh; Lazoğlu, İsmail; PhD Student; Faculty Member; Department of Mechanical Engineering; Manufacturing and Automation Research Center (MARC); College of Engineering; Graduate School of Sciences and Engineering; N/A; N/A; 179391
    The main constraints in high performance machining of the titanium alloys are mostly due to the friction induced thermal issues. In thermal analysis, the friction coefficient is the critical parameter for estimating the heat generation at the tool-chip interface. This paper provides a direct approach for determining the friction coefficient from slot milling of Ti6Al4V for uncoated solid carbide end-mills and AlTiN coated tools with magnetic, friction and sandblast finishing techniques. The effects of AlTiN coating and finishing techniques on friction coefficients are investigated.
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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
    Machining forces and tool deflections in micro milling
    (Elsevier, 2013) Department of Mechanical Engineering; Mamedov, Ali; Khavidaki, Sayed Ehsan Layegh; Lazoğlu, İsmail; Researcher; 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
    The analysis of cutting forces plays an important role for investigation of mechanics and dynamics of cutting process. The importance of force analysis is due to its major role in surface quality of machined parts. Presented force model calculates instantaneous chip thickness by considering trajectory of the tool tip while tool rotates and moves ahead continuously. The model also takes plowing force component into consideration relating it to elastic recovery based on interference volume between tool and workpiece. Based on the mathematical model, distribution of the force acting on the tool is calculated. It is known that this force will create deflection of the tool during cutting, which will result in imperfections of the final part. From this point of view, it is important to predict tool deflections in order to control the cutting process and to avoid failure of the tool. Both force and deflection models are validated on Aerospace Aluminum Alloy (Al-7050), through micro end milling experiments for a wide range of cutting conditions using micro dynamometer and laser displacement sensors. (C) 2013 The Authors. Published by Elsevier B.V.