Prediction of workpiece dynamics and its effects on chatter stability in milling

The workpiece dynamics affect stability in machining of flexible parts. However, it is not a straightforward task to include it in the analysis since the workpiece dynamics continuously change due to mass removal and variation of the cutter contact. In this paper, a methodology for prediction of inprocess workpiece dynamics is presented, which is based on a structural dynamic modification using the FE model of the workpiece. The cutter location (CL) file is used to determine the removed elements at each tool location along a cycle. The proposed approach is demonstrated on example cases, and simulations are verified through experiments. (c) 2012 CIRP.


Stability of Milling Operations With Asymmetric Cutter Dynamics in Rotating Coordinates
Comak, Alptunc; Özşahin, Orkun; Altintas, Yusuf (2016-08-01)
High-speed machine tools have parts with both stationary and rotating dynamics. While spindle housing, column, and table have stationary dynamics, rotating parts may have both symmetric (i.e., spindle shaft and tool holder) and asymmetric dynamics (i.e., two-fluted end mill) due to uneven geometry in two principal directions. This paper presents a stability model of dynamic milling operations with combined stationary and rotating dynamics. The stationary modes are superposed to two orthogonal directions in ...
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...
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...
Analytical modeling of spindle-tool dynamics on machine tools using Timoshenko beam model and receptance coupling for the prediction of tool point FRF
Erturk, A.; Özgüven, Hasan Nevzat; Budak, E. (2006-12-01)
Regenerative chatter is a well-known machining problem that results in unstable cutting process, poor surface quality and reduced material removal rate. This undesired self-excited vibration problem is one of the main obstacles in utilizing the total capacity of a machine tool in production. In order to obtain a chatter-free process on a machining center, stability diagrams can be used. Numerically or analytically, constructing the stability lobe diagram for a certain spindle-holder-tool combination implies...
Development of an iterative method for liquid-propellant combustion chamber instability analysis
Cengiz, Kenan; Özyörük, Yusuf; Department of Aerospace Engineering (2010)
Controlling unsteady combustion induced gas flow fluctuations and the resultant motor vibrations is a very significant step in rocket motor design. It occurs when the unsteady heat release due to combustion happens to feed the acoustic oscillations of the closed duct forming a feed-back system. The resultant vibrations concerned may even lead to total failure of the rocket system unless analysed and tested thoroughly. This thesis aims developing a linear numerical analysis method for the growth rate of inst...
Citation Formats
E. Budak, S. Alan, and H. N. Özgüven, “Prediction of workpiece dynamics and its effects on chatter stability in milling,” CIRP ANNALS-MANUFACTURING TECHNOLOGY, pp. 339–342, 2012, Accessed: 00, 2020. [Online]. Available: