Prediction of frequency response function (FRF) of asymmetric tools from the analytical coupling of spindle and beam models of holder and tool

The prediction of chatter stability diagrams in milling requires accurate frequency response functions (FRF) at the tool - workpiece contact zone. Traditionally, the most accurate FRFs are best obtained through the experimental modal testing of each tool, which is costly. This paper presents analytical modeling and coupling procedures for spindle-holder-tool assemblies with asymmetric tools. Tools and holders are analytically modeled with continuous Timoshenko beams, while considering variation of the cross section geometry of the fluted sections and helix angle. While each solid part segments with varying geometry are assembled with rigid receptance coupling, the holder-spindle and tool-holder are coupled using contact stiffness and damping. The asymmetric cross sections of the helical end mills cause the variation of FRF as a function of the spindle's angular position. It is experimentally proven that the proposed method can predict the FRFs as the asymmetric tools rotate.


Analytical modeling of the machine tool spindle dynamics under operational conditions
Özşahin, Orkun; Özgüven, Hasan Nevzat (null; 2012-07-27)
Chatter is an important problem in machining operations, and can be avoided by utilizing stability diagrams which are generated using frequency response functions (FRF) at the tool tip. In general, tool point FRF is obtained experimentally or analytically for the idle state of the machine. However, during high speed cutting operations, gyroscopic effects and changes of contact stiffness and damping at the interfaces as well as the changes in the bearing properties may lead to variations in the tool point FR...
Selection of design and operational parameters in spindle-holder-tool assemblies for maximum chatter stability by using a new analytical model
Erturk, A.; Budak, E.; Özgüven, Hasan Nevzat (2007-07-01)
In this paper, using the analytical model developed by the authors, the effects of certain system design and operational parameters on the tool point FRF, thus on the chatter stability are studied. Important conclusions are derived regarding the selection of the system parameters at the stage of machine tool design and during a practical application in order to increase chatter stability. It is demonstrated that the stability diagram for an application can be modified in a predictable manner in order to max...
Development of Bolted Flange Design Tool Based on Artificial Neural Network
Yıldırım, Alper; Akay, Ahmet Arda; Gülaşık, Hasan; Çöker, Demirkan; Gürses, Ercan; Kayran, Altan (ASME International, 2019-7-17)
<jats:p>Finite element analysis (FEA) of bolted flange connections is the common methodology for the analysis of bolted flange connections. However, it requires high computational power for model preparation and nonlinear analysis due to contact definitions used between the mating parts. Design of an optimum bolted flange connection requires many costly finite element analyses to be performed to decide on the optimum bolt configuration and minimum flange and casing thicknesses. In this study, very fast resp...
Identification of spindle dynamics by receptance coupling for non-contact excitation system
Özşahin, Orkun; Budak, Erhan; Rabréau, Clément; Le Loch, Sébastien (Elsevier BV; 2019-01-01)
The identification of spindle dynamics plays a crucial role in accurate prediction of the stability diagrams for high speed machining operations. In this study, variations of the mode shapes of the tool-spindle assembly at high spindle speeds are examined using numerical models and hypotheses are formulated. An identification method of spindle dynamics is proposed, dedicated to non-contact excitation system; from which only cross FRF can be obtained (instead of tool tip FRF classically). Then, spindle dynam...
Determination of tool point FRF of micro tools under operational conditions using analytical methods
Özşahin, Orkun (Journal of the Faculty of Engineering and Architecture of Gazi University, 2018-01-01)
Tool point Frequency Response Function (FRF) for micro tools cannot be measured using impact testing and modal analysis. In addition, micro machining operations are performed at high spindle speeds and due to the gyroscopic moments and centrifugal forces tool point FRF changes during machining operations. In this study, micro tools are modeled analytically including the fluted geometry of the tool and operational effects. Moreover, for the machining centers where spindle geometry is unknown, a new coupling ...
Citation Formats
O. Özşahin, “Prediction of frequency response function (FRF) of asymmetric tools from the analytical coupling of spindle and beam models of holder and tool,” INTERNATIONAL JOURNAL OF MACHINE TOOLS & MANUFACTURE, pp. 31–40, 2015, Accessed: 00, 2020. [Online]. Available: