The Influence of Diamond Geometry on the Stability of the Grinding Wheel Dressing Process

1979 ◽  
pp. 607-614 ◽  
Author(s):  
N. P. Fletcher ◽  
H. Maden
Keyword(s):  
Grinding Wheel ◽  
The Stability

The Machining Parameters Online Monitoring Method for Stability Prediction

2011 ◽  
Vol 141 ◽  
pp. 559-563
Author(s):  
Yong Xiang Jiang ◽  
San Peng Deng ◽  
Yu Ming Qi ◽  
Bing Du
Keyword(s):  
Dynamic Models ◽  
Grinding Wheel ◽  
Machining Accuracy ◽  
Machining Parameters ◽  
Regenerative Chatter ◽  
Monitoring Method ◽  
Good Surface ◽  
Prediction And Control ◽  
The Stability ◽  
Online Detecting

Unstable grinding due to the regenerative chatter is one of the most critical errors and a serious limitation to achieve good surface quality. The machining accuracy of CNC is greatly depending on online detecting, prediction and control ability of abnormal phenomena in machining such as chatter. Based on the mechanism of regenerative chatter, the dynamic models of cylindrical plunging are established by considering both the rotate speed of workpiece and grinding wheel. The traverse grinding can be assumed as the sum of several stepwise plunging grinding with respect to the grinding contact area. The stability caused by online detecting indexes of grinding parameters was analyzed. Grinding experiments of online chatter detecting were carried out and agreed well with the theoretical results that show good application future for online chatter detecting.

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.

An Analysis of Centerless Grinding

1964 ◽  
Vol 86 (2) ◽  
pp. 163-174 ◽  
Author(s):  
J. P. Gurney
Keyword(s):  
Transient Behavior ◽  
Analog Computer ◽  
Grinding Wheel ◽  
Machining Processes ◽  
Actual Case ◽  
Centerless Grinding ◽  
Set Up ◽  
The Stability ◽  
Grinding Machine ◽  
Standard Production

Centerless grinding has grown enormously in importance in the last 30 years, until today it is a standard production technique. Instead of the work being supported between centers, as in the older cylindrical grinding, it is supported by means of contact with the grinding wheel, the regulating wheel, and the work blade. In this paper, the methods of analysis already developed and used to examine other machining processes [1, 2] are extended and applied to centerless grinding. Unfortunately, a centerless grinding machine was not available, so it was not possible to apply the analysis to an actual case. The problem was, however, set up on an analog computer, and the effect of changes in various parameters on the stability evaluated. In the light of the results obtained from the computer study the reasons for a number of features of machine-shop practice, evolved by trial and error, can be explained, giving every reason to believe that the analysis is a realistic one. In addition to the stability of the process, the transient behavior inevitably associated with infeed grinding is considered.

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.

A Novel CAM System with X/Y/Z 3-Axis Machines for Large Scale Aspheric Lens Grinding

2010 ◽  
Vol 37-38 ◽  
pp. 23-31
Author(s):  
Xiang Yang Lei ◽  
Hao Huang ◽  
Shi Han Zhang ◽  
Jian Wang ◽  
Qiao Xu ◽  
...  
Keyword(s):  
Error Compensation ◽  
Large Scale ◽  
Grinding Wheel ◽  
Machining Accuracy ◽  
Form Error ◽  
Aspheric Lens ◽  
Geometry Model ◽  
Whole Process ◽  
Nc Program ◽  
The Stability

According to needs of aspheric lens grinding and measurement with X/Y/Z 3-axis grinding machines, a CAM system is designed and implemented. The system, based on the parallel grinding geometry model, has realized the function of grinding locus planning, form error compensation, NC program auto-generation, on-machine measurement, grinding wheel on-machine measurement, simulation and technical database. To verify the stability of this CAM system, experiments were performed with three independent machining experiments. The experimental results indicate that the system realized the whole process of aspheric grinding, and it improved the machining efficiency and automation. Especially, this system adopted on-machine form error compensation technology and improved the machining accuracy. By implementing the error compensation integrated in the CAM system, the surface form error of a 430mm×430mm aspheric lens is decreased from PV8.2µm to PV4.1µm. The grinding accuracy was improved 100%.

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.

Active Vibration Reduction to Optimize the Grinding Process

2009 ◽  
Author(s):  
Alexander L. Boldering ◽  
Marc Simnofske ◽  
Annika Raatz ◽  
Ju¨rgen Hesselbach
Keyword(s):  
Dynamic Stiffness ◽  
Production Quality ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Active Vibration ◽  
Efficient Machine ◽  
High Production ◽  
Basic Approaches ◽  
The Stability ◽  
Grinding Machine

High production quality and processing velocity characterizes an efficient machine tool. Higher velocities lead to increasing process forces, hence the stiffness of the machine must be high. Especially in grinding, the dynamic stiffness of a machine influences the process stability enormously. The stability of the grinding process is affected by the specification of the grinding wheel, machine parameters and the condition of the workpiece. Chattering is simply a consequence of vibration within a grinding system. At present, parts of the machine tools (structures, drives, measuring systems, etc.) are constantly being improved. However, a better performance can only be achieved by applying innovative basic approaches. In this paper, a grinding machine with integrated active modules is presented. The aim of the modules, which consist of piezo actuators and force transducers, is to increase the static and dynamic stiffness of the structure and minimize vibrations.

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.

Open discussion

1982 ◽  
Vol 99 ◽  
pp. 605-613
Author(s):  
P. S. Conti
Keyword(s):  
Buenos Aires ◽  
Large Mass ◽  
List Type ◽  
Common Phenomenon ◽  
Open Discussion ◽  
The Stability ◽  
Ring Nebulae

Conti: One of the main conclusions of the Wolf-Rayet symposium in Buenos Aires was that Wolf-Rayet stars are evolutionary products of massive objects. Some questions:–Do hot helium-rich stars, that are not Wolf-Rayet stars, exist?–What about the stability of helium rich stars of large mass? We know a helium rich star of ∼40 MO. Has the stability something to do with the wind?–Ring nebulae and bubbles : this seems to be a much more common phenomenon than we thought of some years age.–What is the origin of the subtypes? This is important to find a possible matching of scenarios to subtypes.

Symmetric Multistep Methods Revisited: II. Numerical Experiments

1999 ◽  
Vol 173 ◽  
pp. 309-314 ◽  
Author(s):  
T. Fukushima
Keyword(s):  
Multistep Methods ◽  
Computational Time ◽  
Integration Time ◽  
Implicit Methods ◽  
Symmetric Methods ◽  
Celestial Bodies ◽  
The Stability ◽  
Predictor Corrector ◽  
Symmetric Multistep Methods ◽  
Integration Errors

AbstractBy using the stability condition and general formulas developed by Fukushima (1998 = Paper I) we discovered that, just as in the case of the explicit symmetric multistep methods (Quinlan and Tremaine, 1990), when integrating orbital motions of celestial bodies, the implicit symmetric multistep methods used in the predictor-corrector manner lead to integration errors in position which grow linearly with the integration time if the stepsizes adopted are sufficiently small and if the number of corrections is sufficiently large, say two or three. We confirmed also that the symmetric methods (explicit or implicit) would produce the stepsize-dependent instabilities/resonances, which was discovered by A. Toomre in 1991 and confirmed by G.D. Quinlan for some high order explicit methods. Although the implicit methods require twice or more computational time for the same stepsize than the explicit symmetric ones do, they seem to be preferable since they reduce these undesirable features significantly.

Sign in / Sign up

Export Citation Format

Share Document