Dynamic modeling of spindle-tool assemblies in machining centers

Ertürk, Alper
Regenerative chatter is a well-known machining problem that results in unstable cutting process, poor surface quality, reduced material removal rate and damage on the machine tool itself. Stability lobe diagrams supply stable depth of cut ا spindle speed combinations and they can be used to avoid chatter. The main requirement for generating the stability lobe diagrams is the system dynamics information at the tool tip in the form of point frequency response function (FRF). In this work, an analytical model that uses structural coupling and modification methods for modeling the dynamics of spindle-holder-tool assemblies in order to obtain the tool point FRF is presented. The resulting FRF obtained by the model can be used in the existing analytical and numerical models for constructing the stability lobe diagrams. Timoshenko beam theory is used in the model for improved accuracy and the results are compared with those of Euler-Bernoulli beam theory. The importance of using Timoshenko beam theory in the model is pointed out, and the circumstances, under which the theory being used in the model becomes more important, are explained. The model is verified by comparing the results obtained by the model with those of a reliable finite element software for a case study. The computational superiority in using the model developed against the finite element software is also demonstrated. Then, the model is used for studying the effects of bearing and contact dynamics at the spindle-holder and holder-tool interfaces on the tool point FRF. Based on the results of the effect analysis, a new approach is suggested for the identification of bearing and interface parameters from experimental measurements, which is demonstrated on a spindle-holder-tool assembly. The model is also employed for studying the effects of design and operational parameters on the tool point FRF, from the


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...
Investigating the effects of hardening of aluminium alloys on equal-channel angular pressing-A finite-element study
Karpuz, P.; Simsir, C.; Gür, Cemil Hakan (Elsevier BV, 2009-03-15)
Equal-channel angular pressing (ECAP) is a promising severe plastic deformation method for production of ultrafine-grained bulk metals and alloys with considerably improved mechanical properties. In this study, numerical experiments were carried out to investigate the effect of strain hardening of aluminum alloys on the process performance of ECAP via finite element modeling. In the constitutive model, isothermal-plane strain, frictionless condition was assumed. The numerical results showed that strain hard...
Characterization of Duplex Stainless Steel Weld Metals Obtained by Hybrid Plasma-Gas Metal Arc Welding
Yurtışık, Koray; Tirkeş, Süha; Gür, Cemil Hakan; Gürbüz, Rıza (FapUNIFESP (SciELO), 2013-07-01)
Despite its high efficiency, autogenous keyhole welding is not well-accepted for duplex stainless steels because it causes excessive ferrite in as-welded duplex microstructure, which leads to a degradation in toughness and corrosion properties of the material. Combining the deep penetration characteristics of plasma arc welding in keyhole mode and metal deposition capability of gas metal arc welding, hybrid plasma - gas metal arc welding process has considered for providing a proper duplex microstructure wi...
Mixed-mode fracture analysis of orthotropic functionally graded materials under mechanical and thermal loads
Dağ, Serkan; Sarikaya, Duygu (Elsevier BV, 2007-12-01)
Mixed-mode fracture problems of orthotropic functionally graded materials (FGMs) are examined under mechanical and thermal loading conditions. In the case of mechanical loading, an embedded crack in an orthotropic FGM layer is considered. The crack is assumed to be loaded by arbitrary normal and shear tractions that are applied to its surfaces. An analytical solution based on the singular integral equations and a numerical approach based on the enriched finite elements are developed to evaluate the mixed-mo...
An investigation on dynamic contact parameters in machining center spindle tool assemblies
Özşahin, Orkun; Özgüven, Hasan Nevzat; Department of Mechanical Engineering (2008)
In machining centers, with the increasing trends in high precision machining, chatter has become an important problem which results in poor surface finish and low material removal rate. Chatter can be avoided with stability diagrams which provide the stable regions in the machining process for the depth of cut and spindle speed combinations. In order to obtain stability diagrams, tool point frequency response function (FRF) of the system should be obtained. Throughout this study, contact parameters which ar...
Citation Formats
A. Ertürk, “Dynamic modeling of spindle-tool assemblies in machining centers,” M.S. - Master of Science, Middle East Technical University, 2006.