High speed tooltip FRF predictions of arbitrary tool-holder combinations based on operational spindle identification

Postel, M.
Özşahin, Orkun
Altintas, Y.
The chatter vibrations in milling are avoided by selecting spindle speeds and depth of cuts from the stability lobes. However, it has been well observed that the structural dynamics of the spindle system change as a function of speed and even feed. As a result, the measurement of spindle structure's Frequency Response Function (FRF) at zero speed does not lead to an accurate prediction of stability lobes, hence the productive cutting conditions cannot be estimated accurately. In this study, an in-process identification of speed dependent FRF of the spindle structure is proposed. The spindle FRF is either measured during the rotation via impact testing, or FRF is identified from the inverse solution of critical stability limits. The tool-holder is decoupled from the spindle FRF using receptance coupling method, which leads to speed and/or feed dependent spindle shaft FRF. The tool tip FRF is then predicted by coupling the Timoshenko beam based tool-holder to spindle. The proposed method is validated in milling tests. It is shown that the chatter free material removal rates can be more accurately predicted when the spindle speed and feed dependent machine tool dynamics are considered.


Effect analysis of bearing and interface dynamics on tool point FRF for chatter stability in machine tools by using a new analytical model for spindle-tool assemblies
Ertuerk, A.; Özgüven, Hasan Nevzat; Budak, E. (Elsevier BV, 2007-01-01)
Self-excited vibration of the tool, regenerative chatter, can be predicted and eliminated if the stability lobe diagram of the spindle-holder-tool assembly is known. Regardless of the approach being used, analytically or numerically, forming the stability lobe diagram of an assembly implies knowing the point frequency response function (FRF) in receptance form at the tool tip. In this paper, it is aimed to study the effects of spindle-holder and holder-tool interface dynamics, as well as the effects of indi...
Receptance coupling based algorithm for the identification of contact parameters at holder-tool interface
Matthias, W.; Özşahin, Orkun; Altintas, Y.; DENKENA, B. (Elsevier BV, 2016-05-01)
To identify stable cutting conditions with a high depth of cut, stability lobe diagrams are used. In order to predict these diagrams, frequency response functions (FRF) at the tool tip are required for every tool, holder and machine combination. To reduce the number of experimental tests, receptance coupling substructure analysis (RSCA) is proposed in the literature. In order to take full advantage of this method, contact parameters between holder and tool must be known. To identify these parameters this pa...
High-performance parallel hexapod-robotic light abrasive grinding using real-time tool deflection compensation and constant resultant force control
Latifinavid, Masoud; Donder, Abdulhamit; Konukseven, Erhan İlhan (Springer Science and Business Media LLC, 2018-06-01)
In robotic grinding, significant tool deflection occurs due to the lower stiffness of the manipulator and tool, compared with operation by universal grinding machines. Tool deflection during robotic grinding operation causes geometrical errors in the workpiece cross section. Also, it makes difficult to control the grinding cutting depth. In this study, a method is proposed for calculation of the tool deflection in normal and tangential directions based on grinding force feedback in these directions. Based o...
A closed-form approach for identification of dynamical contact parameters in spindle-holder-tool assemblies
Özşahin, Orkun; Özgüven, Hasan Nevzat (Elsevier BV, 2009-01-01)
Accurate identification of contact dynamics is very crucial in predicting the dynamic behavior and chatter stability of spindle-tool assemblies in machining centers. it is well known that the stability lobe diagrams used for predicting regenerative chatter vibrations can be obtained from the tool point frequency response function (FRF) of the system. As previously shown by the authors, contact dynamics at the spindle-holder and holder-tool interfaces as well as the dynamics of bearings affect the tool point...
A modeling approach for analysis and improvement of spindle-holder-tool assembly dynamics
Budak, E.; Erturk, A.; Özgüven, Hasan Nevzat (Elsevier BV, 2006-01-01)
The most important information required for chatter stability analysis is the dynamics of the involved structures, i.e. the frequency response functions (FRFs) which are usually determined experimentally. In this study, the tool point FRF of a spindle-holder-tool assembly is analytically determined by using the receptance coupling and structural modification techniques. Timoshenko's beam model is used for increased accuracy. The spindle is also modeled analytically with elastic supports representing the bea...
Citation Formats
M. Postel, O. Özşahin, and Y. Altintas, “High speed tooltip FRF predictions of arbitrary tool-holder combinations based on operational spindle identification,” INTERNATIONAL JOURNAL OF MACHINE TOOLS & MANUFACTURE, pp. 48–60, 2018, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/46304.