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    Parametric Tolerance Analysis of Rigid Assemblies

    , M.Sc. Thesis Sharif University of Technology Salehvesal, Amir Hossein (Author) ; Movahhedy, Mohammad Reza (Supervisor)
    Abstract
    In a mechanical system, dimensional and geometrical tolerances of components propagate kinematically through assembly and accumulate in a way that alters the critical dimensions of the assembly. Analysis of the accumulation of components tolerances and their influences on the critical dimensions of the assembly (design requirements) and also understanding the behavior of the entire system according to these effects is called tolerance analysis. Tolerance analysis is a key tool in quality improvement, cost reduction and profit growth, and it plays an important role in industrial productions. The Majority of mechanical systems are 3-Dimentional in nature, and approximating them as... 

    Design and manufacturing of High Speed Milling Spindle

    , M.Sc. Thesis Sharif University of Technology Khanzadi, Mostafa (Author) ; Movahhedy, Mohammad Reza (Supervisor) ; Akbari, Javad (Supervisor)
    Abstract
    High speed machining is becoming a progressive trend in machining processes. The main part of a high speed machine tool is its spindle. The purpose of this thesis is to design and manufcture a high speed spindle for milling machine that can rotate at speed of 16000 rpm. This spindle can be used as a test bed for experimental parametric study on the effects of spindle design parameters on the performance of spindle bearings. Various components of the spindle is studied and designed. High speed angular contact bearings and roller bearings are used in the spindle to provide high precision as well as good thermal performance. The spindle is built and tested for high precision machining with... 

    Optimal Design of Tolerances in the Non-rigid Assemblies under the Thermal Impact

    , M.Sc. Thesis Sharif University of Technology Hemati Nik, Javad (Author) ; Khodaygan, Saeed (Supervisor)
    Abstract
    Tolerance allocation in the recent mechanical assembly is significant because it straightly affects product performance and cost. Loose tolerances may cause the quality defect while tight tolerances can increase the cost. Thermal effects and the temperature gradients are one of the factors that caused changes in the size and geometry of the components during the performance of mechanical assemblies. This thesis proposes a new approach for tolerance design considering the thermal effects, to achieve lower manufacturing cost and good product quality. Finite element analysis is used to determine the deformation of components in an assembly. The neural network is trained using experimental... 

    Statistical error analysis for dimensional control in automotive body assembly process

    , Article ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, ESDA2010, 12 July 2010 through 14 July 2010 ; Volume 3 , 2010 , Pages 329-334 ; 9780791849170 (ISBN) Khodaygan, S ; Movahhedy, M. R ; Mirabolghasemi, A ; Zendehbad, M ; Moradi, H ; Sharif University of Technology
    2010
    Abstract
    In mechanical assemblies, the performance, quality, cost and assemblability of the product are significantly affected by the geometric errors of the parts. This paper develops the statistical error analysis approach for dimensional control in automotive body multi-station assembly process. In this method, the homogeneous transformation matrices are used to describe the location and orientation of part and assembly features and the small homogeneous transformation matrices are used to model the errors. In this approach, the effective errors in automotive body assembly process are classified in three categories: manufacturing errors (dimensional and geometric tolerances), locating errors...