Researcher:
Mamedov, Ali

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Ali

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Mamedov

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Mamedov, Ali

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2013 - 20169

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Now showing 1 - 9 of 9
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    Deformation of thin parts in micromilling
    (Elsevier, 2016) Department of Mechanical Engineering; N/A; Lazoğlu, İsmail; Mamedov, Ali; Faculty Member; PHD Student; Department of Mechanical Engineering; College of Engineering; Graduate School of Sciences and Engineering; 179391; N/A
    Deformation is one of the major problems in the micromilling of thin parts. Deformation of thin parts is mainly due to the machining induced residual stresses remained in the part and directly affects the dimensions and form tolerances of microparts. Therefore, this article proposes a new modeling approach to predict deformation of thin parts in micromachining. In the modeling approach, micromilling induced mechanical and thermal loads on the workpiece are estimated, and a new multi-physics based finite element modeling (FEM) approach is proposed to predict thin part deformation in micromilling for the first time. The newly developed deformation model is validated under various cutting conditions in the micromilling of Ti-6Al-4V. (C) 2016 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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    Temperature modeling of micro milling process
    (Japan Society of Mechanical Engineers, 2015) N/A; Department of Mechanical Engineering; Department of Mechanical Engineering; Lazoğlu, İsmail; Mamedov, Ali; Faculty Member; Researcher; Department of Mechanical Engineering; Manufacturing and Automation Research Center (MARC); College of Engineering; College of Engineering; 179391; N/A
    Prediction of the workpiece and tool temperature fields in micro milling of Titanium is important, since it affects the tool wear, has influence on the residual stresses and the 3D distortions of micro parts. An investigation on the temperature of micro milling is performed by considering mechanics and thermal analysis of the process. Considering shearing and frictional heat generations in the primary and secondary zones, temperature fields on the workpiece and on the tool are predicted by Finite Element Analysis. Theoretical simulation and experimental results are presented and discussed.
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    Prediction of residual stress induced distortions in micro-milling of Al7050 thin plate
    (Trans Tech Publications Ltd, 2014) Fergani, Omar; Yang, Jianguo; Liang, Steven Y.; Department of Mechanical Engineering; Department of Mechanical Engineering; Mamedov, Ali; Lazoğlu, İsmail; Researcher; Faculty Member; Department of Mechanical Engineering; College of Engineering; College of Engineering; N/A; 179391
    In this paper, a new analytical model based on a mechanistic force prediction and elastoplastic relaxation procedure predicting the deflections induced by the residual stresses in a milled micro part is proposed. The force model defines the Hertzian type distribution applied by the tool on the part. The proposed deflection model is valid for thin rectangular parts typically produced only using a micro-milling process. The deflection and the force model were analytically developed and experimentally tested on thin Al 7050 micro plates. The force model was validated using micro dynamometer and the deflection profile was verified using the white light interferometer. The proposed model showed that it has a reasonable ability to predict the residual stress induced deflection in the context of stress gradient and intensity.
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    Micro ball-end milling of freeform titanium parts
    (Springer, 2015) N/A; Department of Mechanical Engineering; Department of Mechanical Engineering; Mamedov, Ali; Lazoğlu, İsmail; Researcher; Faculty Member; Department of Mechanical Engineering; Manufacturing and Automation Research Center (MARC); College of Engineering; College of Engineering; N/A; 179391
    Micro machining has growing number of applications in various industries such as biomedical, Automotive, Aerospace, micro-sensor, micro-actuator and jewelry industries. Small-sized freeform titanium parts are frequently needed in the biomedical applications, especially in the implantations such as mini-blood pumps and mini left-ventricular assist devices, finger joint replacements and small bone implants. Most of the small-sized titanium parts with freeform geometries are machined using micro ball-end milling before polishing and other surface treatments. Decreasing the cycle time of the machining parts is important for the productivity. in order to reduce the cycle time of the roughing process in the micro ball-end milling, this paper investigates the implementation of a previously developed force-based feedrate scheduling (FFS) technique on micro milling of freeform titanium parts. after briefly introducing the instantaneous micro milling forces in micro ball-end milling of titanium parts with freeform surfaces, the FFS technique is implemented in the rough machining of a freeform titanium surface to demonstrate the cycle time reduction potentials via virtual micro milling simulations.
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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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    An evaluation of micro milling chip thickness models for the process mechanics
    (Springer London Ltd, 2016) N/A; Department of Mechanical Engineering; Department of Mechanical Engineering; Mamedov, Ali; Lazoğlu, İsmail; Researcher; Faculty Member; Department of Mechanical Engineering; Manufacturing and Automation Research Center (MARC); College of Engineering; College of Engineering; N/A; 179391
    An accuracy of the chip thickness models used in the micro milling mechanics models directly affects the accuracy of the cutting force predictions. There are different chip thickness models derived from various kinematic analyses for the micro milling in the literature. This article presents an evaluation of chip thickness models for micro milling by examining their direct effects on predictions of cutting forces. Performances of four chip thickness models for micro milling existing in the literature are tested and compared with the experimental force measurements. Micro end milling experiments were conducted on an aerospace-grade aluminum alloy Al7050 for different feed rate values. The root mean square deviation and the coefficient of determination values between the estimated and measured micro milling forces are presented for the comparative evaluation of the major chip thickness models at various feed per tooth to tool diameter ratios.
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    Thermal analysis of micro milling titanium alloy Ti-6Al-4V
    (Elsevier Science Sa, 2016) N/A; N/A; Department of Mechanical Engineering; Mamedov, Ali; Lazoğlu, İsmail; Researcher; Faculty Member; Department of Mechanical Engineering; Manufacturing and Automation Research Center (MARC) / Department of Mechanical Engineering; N/A; College of Engineering; N/A; 179391
    This article presents an analysis for micro milling of titanium alloy using finite element modeling and experimental validation. Titanium alloys are commonly used in micro tools for surgery as well as in small size biomedical implants such as miniature left-ventricular assist devices (LVAD), finger joint replacements and small bone implants. Titanium alloys are considered as difficult to machine materials due to their thermo-mechanical properties. Prediction of the temperature fields in the workpiece and the tool during micro milling of Titanium is vital. The temperature in the machining not only affects the tool wear, but also directly influences the residual stresses, 3D distortions and the dimensional accuracy of micro parts. This article presents a finite element model to predict tool and workpiece temperature fields in the micro milling process of Ti-6Al-4V under various cutting conditions. Temperature simulations are validated by thermocouple measurements in the micro milling of Ti-6Al-4V.
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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.