scholarly journals A dynamic model of cylindrical plunge grinding process for chatter phenomena investigation

2018 ◽  
Vol 148 ◽  
pp. 09004
Author(s):  
Paweł Lajmert ◽  
Małgorzata Sikora ◽  
Dariusz Ostrowski
Keyword(s):  
Degrees Of Freedom ◽  
Stability Limit ◽  
Element Model ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Plunge Grinding ◽  
Chatter Vibrations ◽  
Grinding Conditions ◽  
The Stability ◽  
Improved Model

In the paper, chatter vibrations in the cylindrical plunge grinding process are investigated. An improved model of the grinding process was developed which is able to simulate self-excited vibrations due to a regenerative effect on the workpiece and the grinding wheel surface. The model includes a finite-element model of the workpiece, two degrees of freedom model of the grinding wheel headstock and a model of wheel-workpiece geometrical interferences. The model allows to studying the influence of different factors, i.e. workpiece and machine parameters as well as grinding conditions on the stability limit and a chatter vibration growth rate. At the end, simulation results are shown and compared with exemplified real grinding results.

Suppression of Regenerative Chatter in a Plunge-Grinding Process by Spindle Speed

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Yao Yan ◽  
Jian Xu
Keyword(s):  
Control Strategy ◽  
Spindle Speed ◽  
Effective Control ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Regenerative Chatter ◽  
Plunge Grinding ◽  
Dynamical Interaction ◽  
Chatter Vibrations ◽  
Free Region

This paper utilizes an effective control strategy to suppress the regenerative chatter in a plunge-grinding process. To begin with, the dynamical interaction between the workpiece and the grinding wheel is considered as a major factor influencing the grinding stability. Mathematically, the grinding stability is studied through numerical eigenvalue analysis. Consequently, critical chatter boundaries are obtained to distinguish the chatter-free and the chatter regions. As known, the grinding is unstable and the chatter happens in the chatter region. To observe the chatter vibrations, an analytical method and numerical simulations are employed. As a result, chatter vibrations both with and without losing contact between the workpiece and the wheel are obtained. Meanwhile, the coexistence of the chatter and the stable grinding is also found in the chatter-free region. Finally, a control strategy involving spindle speed variation (SSV) is introduced to suppress the chatter. Then, its effectiveness is analytically investigated in terms of the method of multiple scales (MMS).

The Increase of the Dynamic and Static Stiffness of a Grinding Machine

2006 ◽  
Author(s):  
Marc Simnofske ◽  
Ju¨rgen Hesselbach
Keyword(s):  
Dynamic Stiffness ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Static Stiffness ◽  
Process Stability ◽  
Chatter Vibrations ◽  
Theoretical Investigations ◽  
The Stability ◽  
Grinding Machine ◽  
Chatter Marks

The dynamic stiffness of a grinding machine influences the process stability enormously. Among other things the stability of the grinding process is affected by influences like the specification of the grinding wheel, the condition of the workpiece and machine parameters. Unfavorable combinations of these lead to chatter vibrations of the machine and chatter marks on the workpiece. This paper presents the results of experimental and theoretical investigations of the vibration behavior of a grinding machine and the design of active modules. These modules will be implemented in the structure of the machine to minimize the vibrations and additionally increase its static stiffness of the machine.

Stability Analysis of a Transverse Cylindrical Grinding Process

2012 ◽  
Vol 479-481 ◽  
pp. 1190-1193
Author(s):  
Yao Yan ◽  
Jian Xu
Keyword(s):  
Stability Analysis ◽  
Grinding Wheel ◽  
Force Model ◽  
Grinding Process ◽  
Key Factors ◽  
Mass System ◽  
Cylindrical Grinding ◽  
Chatter Vibrations ◽  
The Stability ◽  
Euler Bernoulli Beam

The stability of a transverse cylindrical grinding process is investigated in this paper. The workpiece is considered as a rotating damped hinged-hinged Euler-Bernoulli beam and the grinding wheel a rotating damped spring mass system moving along the workpiece. Called regenerative force, the contact force between the workpiece and the wheel is a functional equation related to both the current and previous relative positions between the workpiece and the wheel since the regeneration exists on the surfaces of both the workpiece and the wheel. The two distinct time delays presented in the regenerative force model are inversely proportional to the rotation speeds of the workpiece and the wheel respectively. For grinding stability analysis, the regenerative effects are considered as the key factors in inducing chatter vibrations in the grinding process. The grinding stability is numerically analyzed since two distinct delays being involved in the model makes the analytical analysis extremely difficult. Finally, the grinding stability analysis is verified by numerical simulation.

An Analytical Design Method for Milling Cutters With Non-Constant Pitch to Increase Stability

2000 ◽  
Author(s):  
Erhan Budak
Keyword(s):  
Surface Finish ◽  
Design Method ◽  
Stability Limit ◽  
Analytical Stability ◽  
Chatter Vibrations ◽  
Constant Pitch ◽  
Improved Stability ◽  
Limited Frequency ◽  
The Stability ◽  
Explicit Relation

Abstract Chatter vibrations result in reduced productivity, poor surface finish and decreased cutting tool life. Milling cutters with non-constant pitch angles can be very effective in improving the stability of the process against chatter. In this paper, an analytical stability model and a design method are presented for non-constant pitch cutters. An explicit relation is obtained between the stability limit and the pitch variation which leads to a simple equation for optimal pitch angles. A certain pitch variation is effective for limited frequency and speed ranges which are also predicted by the model. The improved stability, productivity and surface finish are demonstrated by several examples.

Effects of Relative Velocity on Grinding Performances under Si Wafer Rotary Grinding

2016 ◽  
Vol 874 ◽  
pp. 395-400
Author(s):  
Jumpei Kusuyama ◽  
Takayuki Kitajima ◽  
Akinori Yui ◽  
Toshihiro Ito
Keyword(s):  
Surface Roughness ◽  
Power Consumption ◽  
Relative Velocity ◽  
Velocity Ratio ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Wafer Thickness ◽  
Grinding Conditions ◽  
The Difference ◽  
Si Wafer

For the backgrinding of semiconductor devices, a rotary grinding process is indispensable for achieving the required wafer thickness. The relative velocity between the grinding wheel and the wafer is maximum at the periphery of the wafer and minimum at the center of wafer. Generally, the grinding performances are discussed in terms of the ratio of the rotational speeds of the grinding wheel and the wafer. However, it is not possible to use this ratio to determine the grinding conditions for different wafer sizes grinding as this ratio does not show the difference in relative velocity. Therefore, a new relative velocity ratio was defined in this study. Then, the Si wafer grinding was performed to investigate the effect of the surface roughness and the power consumption of the grinding wheel spindle on the relative velocity ratio.

scholarly journals Thermal deformation rate of grinding wheel in plunge grinding process.

1989 ◽  
Vol 55 (2) ◽  
pp. 354-359 ◽  
Author(s):  
Toshikatsu NAKAJIMA ◽  
Shinya TSUKAMOTO ◽  
Kazunobu SATO
Keyword(s):  
Deformation Rate ◽  
Thermal Deformation ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Plunge Grinding

Nonlinear Stability and Bifurcation of Multi-D.O.F. Chatter System in Grinding Process

2006 ◽  
Vol 304-305 ◽  
pp. 141-145 ◽  
Author(s):  
Qing Kai Han ◽  
Tao Yu ◽  
Zhi Wei Zhang ◽  
Bang Chun Wen
Keyword(s):  
Dynamic Properties ◽  
Grinding Wheel ◽  
Dimensional System ◽  
Grinding Process ◽  
Center Manifold Theorem ◽  
Stability And Bifurcation ◽  
The Stability ◽  
Grinding Machine ◽  
Low Dimensional ◽  
Theoretical Analyses

The nonlinear chatter in grinding machine system is discussed analytically in the paper. In higher speed grinding process, the self-excited chatter vibration is mostly induced by the change of grinding speed and grinding wheel shape. Here the grinding machine tool is viewed as a nonlinear multi-D.O.F. autonomous system, in which hysteretic factors of contact surfaces are also introduced. Firstly, the DOFs of the above system are reduced efficiently without changing its dynamic properties by utilizing the center manifold theorem and averaging method. Then, a low dimensional system and corresponding averaging equations are obtained. The stability and bifurcation of chatter system are discussed on the base of deduced averaging equations. It is proved that chatter occurs as a Hopf bifurcation emerging from the steady state at the origin of system. The theoretical analyses on the multi-DOF chattering system will lead to further understanding of the nonlinear mechanisms of higher speed grinding processes.

The method of assessment of the grinding wheel cutting ability in the plunge grinding

2012 ◽  
Vol 2 (3) ◽  
Author(s):  
Krzysztof Nadolny
Keyword(s):  
Working Conditions ◽  
Comparative Assessment ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Wheels ◽  
Plunge Grinding ◽  
Abrasive Grains ◽  
Ceramic Bond ◽  
Method Of Assessment ◽  
Grinding Kinematics

AbstractThis article presents the method of comparative assessment of the grinding wheel cutting ability in the plunge grinding kinematics. A new method has been developed to facilitate multicriterial assessment of the working conditions of the abrasive grains and the bond bridges, as well as the wear mechanisms of the GWAS, which occur during the grinding process, with simultaneous limitation of the workshop tests range. The work hereby describes the methodology of assessment of the grinding wheel cutting ability in a short grinding test that lasts for 3 seconds, for example, with a specially shaped grinding wheel, in plunge grinding. The grinding wheel macrogeometry modification applied in the developed method consists in forming a cone or a few zones of various diameters on its surface in the dressing cut. It presents an exemplary application of two variants of the method in the internal cylindrical plunge grinding, in 100Cr6 steel. Grinding wheels with microcrystalline corundum grains and ceramic bond underwent assessment. Analysis of the registered machining results showed greater efficacy of the method of cutting using a grinding wheel with zones of various diameters. The method allows for comparative tests upon different grinding wheels, with various grinding parameters and different machined materials.

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