Growing Mechanism of Chatter Vibrations in Grinding Processes and Chatter Stabilization Index of Grinding Wheel

CIRP Annals ◽  
1984 ◽  
Vol 33 (1) ◽  
pp. 259-263 ◽  
Author(s):  
F. Hashimoto ◽  
A. Kanai ◽  
M. Miyashita ◽  
K. Okamura
Keyword(s):  
Grinding Wheel ◽  
Grinding Processes ◽  
Chatter Vibrations ◽  
Stabilization Index

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.

Dressing Monitoring by Acoustic Emission

2005 ◽  
Vol 291-292 ◽  
pp. 195-200 ◽  
Author(s):  
Berend Denkena ◽  
J. Jacobsen ◽  
Niklas Kramer
Keyword(s):  
Acoustic Emission ◽  
Basic Knowledge ◽  
Grinding Wheel ◽  
Acoustic Emission Sensor ◽  
Grinding Processes ◽  
Grinding Machines ◽  
Grinding Time ◽  
Part Production

In modern grinding processes the field of application for vitrified bonded wheels is constantly increasing. Regarding the grinding itself, the advantages of these wheels are obvious. But their ability to be dressed offers further benefits as well. Usually in-machine dressing is favorable. Nevertheless, in-machine dressing causes non-productive-times during which no part production is possible. To reduce this disadvantage, a powerful monitoring is needed in order to minimize the number of needed dressing strokes and to verify the created grinding wheel geometry. The approach applicable for industry is to use an acoustic emission sensor for monitoring, which is usually integrated in modern grinding machines to minimize the air grinding time. This article also provides basic knowledge about Acoustic Emission.

scholarly journals Implicit Subspace Iteration to Improve the Stability Analysis in Grinding Processes

2020 ◽  
Vol 10 (22) ◽  
pp. 8203 ◽  
Author(s):  
Jorge Alvarez ◽  
Mikel Zatarain ◽  
David Barrenetxea ◽  
Jose Ignacio Marquinez ◽  
Borja Izquierdo
Keyword(s):  
Stability Analysis ◽  
Dynamic Stability ◽  
Time Domain ◽  
Grinding Processes ◽  
Subspace Iteration ◽  
Efficient Calculation ◽  
Chatter Vibrations ◽  
Stability Maps ◽  
Iteration Methods ◽  
The Stability

An alternative method is devised for calculating dynamic stability maps in cylindrical and centerless infeed grinding processes. The method is based on the application of the Floquet theorem by repeated time integrations. Without the need of building the transition matrix, this is the most efficient calculation in terms of computation effort compared to previously presented time-domain stability analysis methods (semi-discretization or time-domain simulations). In the analyzed cases, subspace iteration has been up to 130 times faster. One of the advantages of these time-domain methods to the detriment of frequency domain ones is that they can analyze the stability of regenerative chatter with the application of variable workpiece speed, a well-known technique to avoid chatter vibrations in grinding processes so the optimal combination of amplitude and frequency can be selected. Subspace iteration methods also deal with this analysis, providing an efficient solution between 27 and 47 times faster than the abovementioned methods. Validation of this method has been carried out by comparing its accuracy with previous published methods such as semi-discretization, frequency and time-domain simulations, obtaining good correlation in the results of the dynamic stability maps and the instability reduction ratio maps due to the application of variable speed.

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).

Grinding Process Instability

1969 ◽  
Vol 91 (3) ◽  
pp. 597-606 ◽  
Author(s):  
B. Bartalucci ◽  
G. G. Lisini
Keyword(s):  
Closed Loop ◽  
Experimental Tests ◽  
Grinding Wheel ◽  
Closed Loop System ◽  
Regenerative Effect ◽  
Machine Tool Structure ◽  
Chatter Vibrations ◽  
Grinding Machine ◽  
Theoretical Results ◽  
Good Agreement

The paper describes a theoretical investigation on chatter vibrations of cylindrical plunge grinding. The system grinding machine-grinding wheel-workpiece is represented as a closed loop system with two feedback paths, one due to the machine tool structure, the other to the regenerative effect of the grinding wheel. Theoretical results are in good agreement with the experimental tests.

scholarly journals Applications of Contact Length Models in Grinding Processes

2009 ◽  
Vol 404 ◽  
pp. 113-122 ◽  
Author(s):  
H.S. Qi ◽  
B. Mills ◽  
Xi Peng Xu
Keyword(s):  
Contact Length ◽  
Depth Of Cut ◽  
Grinding Wheel ◽  
Grinding Processes ◽  
Orthogonal Relationship ◽  
Creep Feed ◽  
Contact Behaviour ◽  
Wide Range ◽  
The Individual ◽  
Grinding Power

The nature of the contact behaviour between a grinding wheel and a workpiece in the grinding process has a great effect on the grinding temperature and the occurrence of thermal induced damage on the ground workpiece. It is found that the measured contact length le in grinding is considerably longer than the geometric contact length lg and the contact length due to wheel-workpiece deflection lf. The orthogonal relationship among the contact lengths, i.e. lc2 = (Rrlf)2 + lg2, reveals how the grinding force and grinding depth of cut affect the overall contact length between a grinding wheel and a workpiece in grinding processes. To make the orthogonal contact length model easy to use, attempts on modification of the model are carried out in the present study, in which the input variable of the model, Fn’, is replaced by a well-established empirical formula and specific grinding power. By applying the modified model in this paper, an analysis on the contributions of the individual factors, i.e. the wheel/worpiece deformation and the grinding depth of cut, on the overall grinding contact length is conducted under a wide range of grinding applications, i.e. from precise/shallow grinding to deep/creep-feed grinding. Finally, using a case study, the criterion of using geometric contact length lg to represent the real contact length lc, in terms of convenience versus accuracy, is discussed.

Development in the Dressing of Super Abrasive Grinding Wheels

2009 ◽  
Vol 404 ◽  
pp. 1-10 ◽  
Author(s):  
Berend Denkena ◽  
Luis de Leon ◽  
B. Wang ◽  
Dennis Hahmann
Keyword(s):  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Grinding Wheel ◽  
Grinding Wheels ◽  
Fine Grained ◽  
Grinding Processes ◽  
Shifting Strategy ◽  
Contact Discharge

Harder workpiece materials and increased efficiency requirements for grinding processes make the use of super abrasive grinding wheels indispensable. This paper presents newly developed processes for the dressing of super abrasive grinding wheels. The different bond systems of grinding wheels require distinct dressing process. In this paper, dressing processes for metal and vitrified bonded grinding wheels are investigated. It introduces the method of electro contact discharge dressing for the conditioning of metal-bonded, fine-grained multilayer grinding wheels. A description of the essential correlation between dressing parameters and the material removal rate of the bond material is presented. The considered parameters are the dressing voltage, the limitation of the dressing current and the feed as well as the infeed of the electrode. For the grinding of functional microgroove structures, multiroof profiles with microscopic tip geometries are dressed onto the grinding wheel. For this, a profile roller in combination with a special shifting strategy is applied on finegrained vitrified bonded grinding wheels.

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