Investigating Dynamics of Machine Tool Spindles under Operational Conditions

2011-05-13
Chatter is one of the major problems in machining and can be avoided by stability diagrams which are generated using frequency response functions (FRF) at the tool tip. During cutting operations, discrepancies between the stability diagrams obtained by using FRFs measured at the idle state and the actual stability of the process are frequently observed. These deviations can be attributed to the changes of machine dynamics under cutting conditions. In this paper, the effects of the cutting process on the spindle dynamics are investigated both experimentally and analytically. The variations in the spindle dynamics are attributed to the changes in the bearing parameters. FRFs under cutting conditions are obtained through the input-output relations of the cutting forces and the vibration response which are measured simultaneously. Experimentally and analytically obtained FRFs are then used in the identification of the bearing parameters under cutting conditions. Thus, bearing properties obtained at idle and cutting conditions are compared and variations in their values are obtained.

Suggestions

A computational procedure for estimating residual stresses and secondary plastic flow limits in nonlinearly strain hardening rotating shafts
Eraslan, Ahmet Nedim (Springer Science and Business Media LLC, 2005-03-01)
A computational procedure to estimate the residual stress distributions and the limit angular speeds for avoiding secondary plastic deformation in nonlinearly strain hardening rotating elastic-plastic shafts is given. The model is based on von Mises yield condition, J(2) deformation theory and a Swift-type hardening law. The boundary value problem for the governing nonlinear differential equation is solved by a shooting method using Newton iterations with numerically approximated tangent. Solid as well as h...
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 ...
RECONSTRUCTION OF PERMITTIVITY AND CONDUCTIVITY PROFILES OF A DIELECTRIC SLAB IN THE TIME DOMAIN BY DESCENT METHODS
ONDER, M; Kuzuoğlu, Mustafa (Institution of Engineering and Technology (IET), 1992-10-01)
An optimisation approach is presented for the problem of reconstructing the permittivity and conductivity profiles of a dielectric slab from the reflected and transmitted field data. The problem is treated as an optimal control problem where the norm of the difference of measured and calculated boundary data is minimised subject to the state equation governing the system. The original constrained optimisation problem is reduced to the evaluation of stationary points of an augmented functional which is obtai...
The rotating elastic-plastic hollow shaft conveying a hot medium
Arslan, E.; Mack, W.; Eraslan, Ahmet Nedim (Springer Science and Business Media LLC, 2010-03-01)
Based on Tresca's yield criterion and the flow rule associated with it, the distribution of stress and strain in a linearly strain hardening elastic-plastic hollow shaft subject to monotonously increasing angular speed and a negative radial temperature gradient-corresponding to the flow of a hot medium-is investigated. Presupposing circular symmetry and plane strain conditions, the problem is amenable to an analytical treatment. It is found that-depending on the temperature difference between the outer and ...
Generalized beam angle statistics for shape descrition
Tola, Ömer Önder; Yarman Vural, Fatoş Tunay; Department of Computer Engineering (2004)
In this thesis, we introduce a new shape descriptor and a graph based matching algorithm to detect a template shape in an image that contains a single object. The shape descriptor, Generalized Beam Angle Statistics, GBAS is obtained with the generalization of the boundary based shape descriptor, Beam Angle Statistics, BAS
Citation Formats
O. Özşahin and H. N. Özgüven, “Investigating Dynamics of Machine Tool Spindles under Operational Conditions,” 2011, vol. 223, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/49161.