Journal articles: 'Mode coupling chatter'

1

Gasparetto, Alessandro. "A System Theory Approach to Mode Coupling Chatter in Machining." Journal of Dynamic Systems, Measurement, and Control 120, no. 4 (1998): 545–47. http://dx.doi.org/10.1115/1.2801501.

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Chatter is an undesired phenomenon of self-excited vibrations that occurs during many machining operations. This paper analyzes mode coupling chatter from the point-of-view of the system theory. A simplified mathematical model of the cutting process is established, from which the equations of the system are obtained. Then, the eigenvalues and the eigenvectors of the system are evaluated, and a simple stability condition is formulated. The tool trajectories both in the stable and unstable case are studied. Finally, an example of mode coupling chatter in a machine for wood cutting and its stabilization is presented.

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Yun, I.-S., K. F. Ehmann, and W. R. D. Wilson. "Chatter in the Strip Rolling Process, Part 3: Chatter Model." Journal of Manufacturing Science and Engineering 120, no. 2 (1998): 343–48. http://dx.doi.org/10.1115/1.2830133.

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The central problem of the analysis and prevention of chatter in rolling operations is in understanding the conditions which lead to dynamic instability. By analogy with metal cutting operations, it appears that a few basic mechanisms may be responsible for the occurrence of self-excited vibrations in rolling. The three most significant mechanisms are: negative damping, mode-coupling and regeneration. In this paper, negative damping and mode-coupling are considered separately in an “artificial” manner to make inroads toward a better basic understanding of rolling instability.

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Celikag, Huseyin, Erdem Ozturk, and Neil D. Sims. "Can mode coupling chatter happen in milling?" International Journal of Machine Tools and Manufacture 165 (June 2021): 103738. http://dx.doi.org/10.1016/j.ijmachtools.2021.103738.

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Ismail, F., and A. Bastami. "Improving Stability of Slender End Mills Against Chatter." Journal of Engineering for Industry 108, no. 4 (1986): 264–68. http://dx.doi.org/10.1115/1.3187076.

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The strongest mechanisms that contribute to machining chatter are regeneration and mode coupling. Special designs of milling cutters have evolved with the aim to increase stability against chatter by disturbing the regeneration mechanism. However, in the case of slender end mills, the mode coupling remains most active. In this work, a new approach is presented where a design change of the cutter is suggested to weaken the mode coupling mechanism. Time domain simulation of the development of chatter showed that using this approach significant increase in stability could be achieved. Cutting tests of aluminum with the modified end mills confirmed simulation results.

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Badiola, X., A. Iturrospe, J. M. Abete, and P. J. Arrazola. "State–space analysis of mode-coupling workpiece chatter." International Journal of Advanced Manufacturing Technology 103, no. 5-8 (2019): 2773–81. http://dx.doi.org/10.1007/s00170-019-03737-8.

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He, Feng-Xia, Li Dai, Qisen Chen, Yu Liu, and Zhong Luo. "Three-dimensional stability analysis of robotic machining process." Industrial Robot: the international journal of robotics research and application 47, no. 1 (2019): 82–89. http://dx.doi.org/10.1108/ir-02-2019-0036.

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Purpose Since robot’s structural stiffness is usually less than 1 N/µm, mode coupling chatter occurs frequently during robotic milling process, and chatter frequency is close to the natural frequency of the robot itself. Chatter not only affects the surface quality but also damages the robot and reduces the positioning accuracy. Therefore, it is necessary to predict chatter in robotic machining process. Design/methodology/approach A three-dimensional dynamic model for robot’s spatial milling plane is established, and a corresponding stability criterion is obtained. First, the cutting force in milling plane is transformed into the coordinate system of the robot principal stiffness direction based on homogeneous transformation matrix. Then the three-dimensional stability criterion under milling process can be obtained by using system stability analysis. Furthermore, the circle diagram of mode coupling chatter stability is drawn. Each feeding direction’s stability under the two processing forms, referred as spindle vertical milling and spindle horizontal milling, is analyzed. Findings The experimental results verify that the three-dimensional stability criterion can avoid chatter by selecting machining feed direction in stable area. Originality/value This paper established a three-dimensional dynamic model in robot’s spatial milling plane and proposed a three-dimensional stability criterion according to the Routh criterion. The work is also expected to be an efficient tool in the development of robotic milling technology.

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Cen, Lejun, and Shreyes N. Melkote. "CCT-based mode coupling chatter avoidance in robotic milling." Journal of Manufacturing Processes 29 (October 2017): 50–61. http://dx.doi.org/10.1016/j.jmapro.2017.06.010.

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Gienke, Orm, Zengxi Pan, Lei Yuan, Thomas Lepper, and Stephen Van Duin. "Mode coupling chatter prediction and avoidance in robotic machining process." International Journal of Advanced Manufacturing Technology 104, no. 5-8 (2019): 2103–16. http://dx.doi.org/10.1007/s00170-019-04053-x.

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Gasparetto, Alessandro. "Eigenvalue Analysis of Mode-Coupling Chatter for Machine-Tool Stabilization." Journal of Vibration and Control 7, no. 2 (2001): 181–97. http://dx.doi.org/10.1177/107754630100700203.

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Wu, D. W., and C. R. Liu. "An Analytical Model of Cutting Dynamics. Part 1: Model Building." Journal of Engineering for Industry 107, no. 2 (1985): 107–11. http://dx.doi.org/10.1115/1.3185972.

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A mathematical model of machining chatter has been developed through an analytical approach in order to predict dynamic cutting force from steady-state cutting tests. The model is derived from a pseudo-static geometric configuration of the cutting process by taking into account the fact that the mean friction coefficient fluctuates dynamically responding to variation of the relative speed on the chip-tool interface. The force functions through this derivation can be used to explain all three basic mechanics associated with chatter vibration, namely, velocity dependent, regenerative, and mode coupling effects.

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Nurul Amin, A. K. M., Muammer Din Arif, Muhd Amir Hafiz B. Ahamad Mohrodi, and Israd H. Jaafar. "Development of Mathematical Model for Chip Serration Frequency in Turning of Stainless Steel with Magnetic Damping from Tool Side." Applied Mechanics and Materials 394 (September 2013): 211–16. http://dx.doi.org/10.4028/www.scientific.net/amm.394.211.

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Chatter, the self-excited and violent oscillatory motion between the tool and the work-piece, is detrimental to all machining operations, especially turning. It can lead to poor surface topography, reduced productivity, excessive tool wear, and damaged machine-tool components. Several theories have been introduced to explain chatter, but their predictions have not always been reliable. Therefore, chatter avoidance has relied on inefficient techniques like limiting material removal rates or expensive setups such as actuators and ultrasonic vibration damping systems. However, a deeper investigation into chatter formation reveals that chip morphology and segmentation play a significant role during incidence of machining chatter. The novel Resonance theory of chatter combines the concept of mode coupling of the machining setup and serrated chip formation, to explain the incidence of chatter. To validate the postulates of this theory, models for chip serration frequency are essential. At the same time, a reliable and economical chatter control method is required. To this end, the current research work developed an empirical mathematical model of chip serration frequency in turning of stainless steel AISI 304 using Response Surface Methodology (RSM). Also, it investigated the influence of damping provided by magnetic field from a permanent magnet. The developed chip serration model shows good agreement with experimental data.

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Amin, A. K. M. Nurul, Fawaz Mohsen Abdullah, Muammer Din Arif, and Israd H. Jaafar. "Mathematical Model for Chip Serration Frequency in Turning of Stainless Steel with Magnetic Damping from Bottom of Tool Shank." Applied Mechanics and Materials 393 (September 2013): 108–14. http://dx.doi.org/10.4028/www.scientific.net/amm.393.108.

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Chatter, a violent and often unpredictable relative oscillatory motion between the tool and work-piece, is a serious concern in turning operations. Its occurrence is usually associated with a loud monotonous sound and usually results in increased surface roughness, reduced material removal rates, shortened tool life, and damaged machine-tool bearings. The established theories for chatter are very limited in scope and are often contradicted by empirical evidences. Therefore, chatter avoidance in the past has relied on inefficient techniques like limiting material removal rates or expensive setups such as actuators and ultrasonic vibration damping systems. However, a deeper investigation into chatter formation reveals that chip morphology and segmentation play a significant role during the incidence of chatter. The novel Resonance theory of chatter combines the concept of mode coupling of the machining setup and serrated chip formation, to explain and predict chatter. To validate the postulates of this theory, models for chip serration frequency are essential. At the same time, a reliable and economical chatter control method is required. With this goal, the current research work has developed an empirical mathematical model of chip serration frequency in turning of stainless steel AISI 304 using Response Surface Methodology (RSM). Also, it investigated the influence of damping provided by magnetic field from a permanent ferrite magnet placed beneath the tool shank. The developed chip serration model is in good accord with the experimental data, demonstrating that the empirical model could be used for further chip morphology and chatter analyses.

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Li, Zhongyun, Shanglei Jiang, and Yuwen Sun. "Chatter stability and surface location error predictions in milling with mode coupling and process damping." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 233, no. 3 (2017): 686–98. http://dx.doi.org/10.1177/0954405417708225.

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Together with machining chatter, surface location error induced by forced vibration may also inhibit productivity and affect workpiece surface quality in milling process. Addressing these issues needs the combined consideration of stability lobes diagram and surface location error predictions. However, mode coupling and process damping are seldom taken into consideration. In this article, an extended dynamic milling model including mode coupling and process damping is first built based on classical 2-degree-of-freedom dynamic model with regeneration. Then, a second-order semi-discretization method is proposed to simultaneously predict the stability lobes diagram and surface location error by solving this extended dynamic model. The rate of convergence of the proposed method is also investigated. Finally, a series of experiments are conducted to verify the veracity of the extended dynamic model. The modal parameters including direct and cross terms are identified by impact experiments. Via experimental verification, the experimental results show a good correlation with the predicted stability lobes diagram and surface location error based on the extended dynamic model. Also, the effects of mode coupling and process damping are revealed. Mode coupling increases the whole stability region; however, process damping plays a vital role in stability improvement mainly at low spindle speeds.

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Jafarzadeh, Ehsan, and Mohammad R. Movahhedy. "Numerical simulation of interaction of mode-coupling and regenerative chatter in machining." Journal of Manufacturing Processes 27 (June 2017): 252–60. http://dx.doi.org/10.1016/j.jmapro.2017.05.008.

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Ismail, F., and V. R. Vadari. "Machining Chatter of End Mills With Unequal Modes." Journal of Engineering for Industry 112, no. 3 (1990): 229–35. http://dx.doi.org/10.1115/1.2899579.

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This paper further investigates the effect of reducing the contribution of the mode coupling mechanism to machining chatter. This reduction was achieved in a previous investigation by making the cutting tool more compliant in one direction. Thus, in particular, the objective of the present work was to study the effect of varying the orientation angle between the flexible mode and the leading edge of the first cutting tooth. The study covered slotting and half immersion, up and down milling. The modified cutters, irrespective of the orientation angle, are shown to outperform the regular cutter in slotting over a wide speed range. This angle is found to have a very strong effect in half immersion. The study is conducted using both computer simulation and cutting tests using aluminum.

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Yuan, Lei, Shuaishuai Sun, Zengxi Pan, Donghong Ding, Orm Gienke, and Weihua Li. "Mode coupling chatter suppression for robotic machining using semi-active magnetorheological elastomers absorber." Mechanical Systems and Signal Processing 117 (February 2019): 221–37. http://dx.doi.org/10.1016/j.ymssp.2018.07.051.

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Nguyen, Vinh, Shreyes Melkote, Amar Deshamudre, and Maneesh Khanna. "PVDF sensor based on-line mode coupling chatter detection in the boring process." Manufacturing Letters 16 (April 2018): 40–43. http://dx.doi.org/10.1016/j.mfglet.2018.04.004.

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OTA, Hiroshi, Masashi KITO, and Tsuyoshi HANDA. "A Study on Primary Chatter Caused by Mode Coupling of Machine Tool Structure." Transactions of the Japan Society of Mechanical Engineers Series C 73, no. 726 (2007): 570–76. http://dx.doi.org/10.1299/kikaic.73.570.

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Yuan, Lei, Zengxi Pan, Donghong Ding, Shuaishuai Sun, and Weihua Li. "A Review on Chatter in Robotic Machining Process Regarding Both Regenerative and Mode Coupling Mechanism." IEEE/ASME Transactions on Mechatronics 23, no. 5 (2018): 2240–51. http://dx.doi.org/10.1109/tmech.2018.2864652.

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Merdol, S. D., and Y. Altintas. "Multi Frequency Solution of Chatter Stability for Low Immersion Milling." Journal of Manufacturing Science and Engineering 126, no. 3 (2004): 459–66. http://dx.doi.org/10.1115/1.1765139.

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Finish milling is usually required in the peripheral milling of thin aircraft webs with long end mills, where the structures are flexible and radial depths of cut are small. The spindle speed and depth of cut must be selected optimally to avoid both forced and chatter vibrations, which in turn enables production of the parts within specified tolerances. Recent articles show that stability pockets differ at certain speeds when the radial immersion in milling is low and the machining process is highly intermittent. This paper presents a stability theory which predicts chatter stability lobes that are not covered by classical chatter theories in which the coupling between the spindle speed and process stability are neglected. The dynamics of low radial immersion milling are formulated as an eigenvalue problem, where harmonics of the tooth spacing angle and spread of the transfer function with the harmonics of the tooth passing frequencies are considered. It is shown that the stability lobes are accurately predicted with the presented method. This paper details the physics involved when the tooth passing frequencies alter the effective transfer function of the structure in the stability solution. The products of the harmonics of the directional coefficients and transfer functions of the structure are evaluated at the natural mode under the influence of tooth passing frequency harmonics in order to obtain the exact locations of chatter stability lobes.

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KONDO, Eiji, Hideho TANAKA, and Norio KAWAGOISHI. "Detection of Self-Excited Chatter Caused by Mode Coupling. 1st Report. Study on Criterion of Detection." Transactions of the Japan Society of Mechanical Engineers Series C 64, no. 625 (1998): 3661–66. http://dx.doi.org/10.1299/kikaic.64.3661.

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Zhang, Keguo, and Xiaodong Xu. "Vibration Transmission and Isolation in the Cutting Process of Machine Tools." Recent Patents on Mechanical Engineering 12, no. 1 (2019): 65–71. http://dx.doi.org/10.2174/2212797612666181213102904.

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Background: Machining is an important method for manufacturing parts. It is characterized by high cutting speed with a considerable influence of high-frequency vibration. Various relevant papers and patents have studied vibration transmission and isolation in the machining process. Objective: To investigate vibration transmission and isolation in the machining process, and simplify the cutting process of a machine tool. Methods: Firstly single-layer and double-layer vibration isolation models are established, the substructure matrix analysis method is adopted and the vibration power flow transmission characteristics of double-layer vibration isolation system under complex excitation are analyzed. Secondly, the optimal control strategy based on the minimum power flow inputted into the base is proposed. Then the control effect of the active actuator under different installation modes is analysed and compared. Results: It has been proved that low-frequency coupling is characterized by the rigid mode of the workpiece or the grinding wheel when cutting, whereas high-frequency coupling exhibits the dynamic characteristics of the machine tool bed. A good vibration isolation effect can be achieved for three types of installation modes in a double-layer vibration isolation system, and only the actuators installed between the vibration source and the middle mass exhibit the best control effect. Conclusion: The vibration isolation model has been established and the optimal installation mode of the actuator in the double-layer vibration isolation system has been found. And the paper provides a reference for the study of vibration transmission, control of machine tools and the elimination of grinding chatter.

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Bayly, Philip V., Sandra A. Metzler, Adam J. Schaut, and Keith A. Young. "Theory of Torsional Chatter in Twist Drills: Model, Stability Analysis and Composition to Test." Journal of Manufacturing Science and Engineering 123, no. 4 (2000): 552–61. http://dx.doi.org/10.1115/1.1381399.

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The mechanism of torsional chatter in drilling differs qualitatively and quantitatively from other types of chatter. In this paper we show that torsional chatter can be explained by the torsional-axial coupling inherent in a twisted beam; the beam “untwists” and extends in response to an increase in cutting torque. Based on a model of this mechanism, predictions of stability boundaries and chatter frequencies are derived by frequency domain analysis, and confirmed by numerical simulation and experimental tests. The effect of the torsional-axial coupling is opposite that of traditional cutting in that an increase in cutting forces leads to axial extension and greater chip load. Because of this sign difference, the limiting depth of cut is governed by the positive real part of the frequency response function, which explains the unexpected fact that torsional chatter occurs below the natural frequency of the tool.

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Hattori, Kosuke, Hiroyuki Kodama, Toshiki Hirogaki, and Eiichi Aoyama. "Investigation of Chatter Vibration in End-Milling Process by Considering Coupled System Model." Advanced Materials Research 939 (May 2014): 201–8. http://dx.doi.org/10.4028/www.scientific.net/amr.939.201.

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Chatter vibration in cutting processes usually leads to surface finish degradation, tool damage, cutting noise, energy loss, etc. Self-excited vibration particularly seems to be a problem that is easily increased to large vibration. The regenerative effect is considered as one of the causes of chatter vibration. Although the chatter vibration occurs in various types of processing, the end-milling is a typical process that seems to cause the chatter vibration due to a lack of rigidity of one or more parts of the machine tools, cutting tool, and work-piece. The aim of our research is to propose a simple method to control chatter vibration of the end-milling process on the basis of a coupling model integrating the related various elements. In this study, hammering tests were carried out to measure the transfer function of a machine tool and cutting tool system, which seems to cause vibration. By comparing these results, finite elemental method (FEM) analysis models were constructed. Additionally, cutting experiments were carried out to confirm the chatter vibration frequencies in end-milling with a machining center. In the hammering tests, impulse hammer and multiple acceleration pick-ups are connected to a multi-channel FFT analyzer and estimate the natural frequencies and natural vibration modes. A simplified FEM model is proposed by circular section stepped beam elements on the basis of the hammering test results, considering a coupling effect. In comparisons of the calculated results and hammering test results, the vibration modes are in good agreement. As a result, the proposed model accurately predicts the chatter vibration considering several effects among the relating elements in end-milling. Moreover, it can be seen that the chatter vibration is investigated from a viewpoint of the integrating model of the end-milling process.

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Chiou, R. Y. S., and S. Y. Liang. "Chatter Frequency in Turning Considering Tool Compliance and Wearland." Journal of Manufacturing Science and Engineering 121, no. 2 (1999): 307–11. http://dx.doi.org/10.1115/1.2831221.

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An analytical model for the chatter frequency of a turning cutter considering system compliance and flank wear of the tool is presented in this research. The fundamental mechanism of selfexcited vibration at the presence of tool wearland is examined, and a mathematical model is developed to describe the frequency characteristics of the vibration. In the paper a comparison of the chatter frequencies for a fresh cutting tool and a worn cutting tool is provided to demonstrate the coupling between wearland and chatter. The theoretical model of chatter frequency is validated by experimental observations over a range of turning conditions.

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Yang, Xu, Chao-nan Tong, Guang-feng Yue, and Jian-ji Meng. "Coupling dynamic model of chatter for cold rolling." Journal of Iron and Steel Research International 17, no. 12 (2010): 30–34. http://dx.doi.org/10.1016/s1006-706x(10)60193-8.

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Lu, Xing, Jie Sun, Guangtao Li, Zhenhua Wang, and Dianhua Zhang. "Stability Analysis of a Nonlinear Coupled Vibration Model in a Tandem Cold Rolling Mill." Shock and Vibration 2019 (February 17, 2019): 1–14. http://dx.doi.org/10.1155/2019/4358631.

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Mill chatter in tandem cold rolling mill is a major rejection to the quality and production of the strips. In most mill vibration models, either the roll mass is usually limited to vibrate in vertical direction and vertical-horizontal directions, or the multiple rolls system is simplified to a single mass system. However, the torsional chatter is also a typical type of mill chatter, and the presence of intermediate roll and backup roll will affect the overall vibration of the mill structure system. In this paper, a newly cold rolling mill vibration model coupled with the dynamic rolling processing model and nonlinear vibration model is proposed with the consideration of dynamic coupling and nonlinear characteristics of the rolling process, multiroll equilibrium, and roll movement in both vertical-horizontal-torsional directions. By using Hopf bifurcation theorem and Routh–Hurwitz determinant, the existence of the Hopf bifurcation point of the mill vibration system and bifurcation characteristics are analyzed. At last, the influence of different rolling conditions on the stability of the coupled mill system is investigated, and these results can also be used to design an optimum rolling schedule and determine the appearance of mill chatter under certain rolling conditions.

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Cui, Li, and Yin Su. "Chatter Stability Prediction Method of the Spindle-Tool Holder-Tool System with Interface Contact Characteristics." Mathematical Problems in Engineering 2020 (December 5, 2020): 1–15. http://dx.doi.org/10.1155/2020/7121328.

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To predict chatter stability and suppress chatter vibration, a chatter stability prediction method for the spindle-tool holder-tool system with interface contact characteristics is constructed. A five-DOF model is constructed to determine the spindle-bearing interface dynamic contact stiffness considering the coupling effect of spindle and bearing. A fractal multiscale tool holder-spindle interface dynamic stiffness model is proposed considering time-varying cutting force. The fractal dimensions and cutting force coefficient parameters are identified from the power spectrum experiments and cutting force tests. The cutting force is solved according to the milling stability model. Dynamic model of the spindle-tool holder-tool system is found by the finite element method. Based on extended Floquet theory, chatter stability of the spindle system is studied. Effect of interface parameters, radial cutting depth, and feed rate on milling stability is researched. Milling force tests and milling stability tests are performed in order to verify the reliability of the method. Results find that the increase of front bearing preload and spindle-tool holder’s interference fit are effective to improve the milling stability. The optimal feed rate and the critical radial cutting depth are found. The model proposed in this paper can be used as an instruction for predicting and suppressing the chatter vibration and optimizing cutting parameters and also is helpful for designing the spindle-tool holder-tool system.

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Hao, Daxian, Wei Wang, Zhaoheng Liu, and Chao Yun. "Experimental study of stability prediction for high-speed robotic milling of aluminum." Journal of Vibration and Control 26, no. 7-8 (2019): 387–98. http://dx.doi.org/10.1177/1077546319880376.

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It has been fully demonstrated that the regenerative chatter theory is applicable for predicting chatter-free milling parameters for computer numerical control machine tools, but researchers are still arguing whether it is effective for robotic milling processes. The main reason is that the robot’s modes greatly shift, depending on its varying dynamic parameters and joint configurations. More experimental investigations are required to study and better understand the mechanism of vibration in robotic machining. The present paper is focusing on finding experimental support for chatter-free prediction in robot high-speed milling by the regenerative chatter theory. Modal tests are first conducted on a milling robot and used to predict stability lobes by zeroth order approximation. A number of high-speed slotting tests are then carried out to verify the prediction results. Thus, the regenerative chatter theory is proved to be also applicable to robotic high-speed milling. Furthermore, low-frequency modes of the robot structure are investigated by more modal experiments involving a laser tracker and a displacement sensor. The low-frequency modes are identified as the main part of the prediction error of the zeroth order approximation method, which could also be dominant in low-speed robotic milling processes. In addition, robots are different from computer numerical control machines in terms of stiffness, trajectory following error, forced vibration, and motion coupling. These long-period trend terms have to be carefully taken into account in the regenerative chatter theory for robotic high-speed milling.

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Liu, Xiaochan, Yong Zang, Zhiying Gao, and Lingqiang Zeng. "Time Delay Effect on Regenerative Chatter in Tandem Rolling Mills." Shock and Vibration 2016 (2016): 1–15. http://dx.doi.org/10.1155/2016/4025650.

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The interstand tension coupling effect and strip gauge variation passed on to next stand with time delay are the main causes for regenerative chatter in tandem rolling mills. To study the effect of different factors on the stability of tandem rolling mills, different models considering different interstand factors were built. Through stability analysis of these models by employing the Lyapunov indirect method and integral criterion, more detailed and quantitative explanation is put forward to regenerative chatter mechanism in rolling. To study the time delay effect as a single factor on the stability of tandem rolling mills, stability charts of the chatter model including the time delay effect and model neglecting the delay time were compared. The results show that the time delay effect reduces the critical velocity of multistand mills slightly in the big picture. But it alters the relationship between two adjacent stands by worsening the downstream stand stability. To get preferable rolling process parameter configuration for the tandem rolling mills, the time delay effect in rolling must be involved.

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Fan, Xiao-bin, Yong Zang, Yuan-kui Sun, and Ping-an Wang. "Impact Analysis of Roller System Stability for Four-High Mill Horizontal Vibration." Shock and Vibration 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/5693584.

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In order to study the hot Compact Strip Production (CSP), four-high mill vibration characteristics, and vibration suppression method, the roller system structure stability was analyzed and calculated at first in the paper. And then, the mill stand gap was measured at field and its influence on roll transverse vibration was analyzed. The drum gear coupling effect on the roller system stability and the automatic balance conditions of the coupling transmission torque were studied; the influence of axial force caused by the roller cross on the system stability was analyzed. Finally, the roller transverse friction chatter vibration mechanics model was established; the simulation analysis was carried out with eliminating mill house-bearing clearance and adding floating support for coupling, respectively. And the characteristics of the roller “jump vibration” were studied. We applied copper gaskets to eliminate or reduce mill house-bearing clearance for suppressing the rolling mill vibration on the spot; the test results show that the roller transverse vibration was suppressed after eliminating clearance.

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Chen, C. H., and K. W. Wang. "An Integrated Approach Toward the Dynamic Analysis of High-Speed Spindles: Part 2—Dynamics Under Moving End Load." Journal of Vibration and Acoustics 116, no. 4 (1994): 514–22. http://dx.doi.org/10.1115/1.2930457.

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This paper presents an integrated study of a rotor/bearing structure, with specific interests toward high-speed spindle systems under rotating end loads. Considering the coupling between the rotating shaft and the nonlinear bearings, an iterative method is developed to derive the system equilibrium configuration for given operating conditions. With moving end loads, structural instability caused by high rotational speed is analyzed. The critical speeds and unstable speed regions are discussed. Machining chatter instability lobes are also derived using the spindle model. It is shown that significant errors will occur in predicting spindle characteristics and stability if the speed and load effects on the shaft/bearing dynamics are neglected.

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Mancisidor, Iker, Mikel Zatarain, Jokin Munoa, and Zoltan Dombovari. "Fixed Boundaries Receptance Coupling Substructure Analysis for Tool Point Dynamics Prediction." Advanced Materials Research 223 (April 2011): 622–31. http://dx.doi.org/10.4028/www.scientific.net/amr.223.622.

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In many applications, chatter free machining is limited by the flexibility of the tool. Estimation of that capacity requires to obtain the dynamic transfer function at the tool tip. Experimental calculation of that Frequency Response Function (FRF) is a time consuming process, because it must be done using an impact test for any combination of tool, toolholder and machine. The bibliography proposes the Receptance Coupling Substructure Analysis (RCSA) to reduce the number of experimental test. A new approach consisting of calculating the fixed boundary dynamic behaviour of the tool is proposed in the paper. This way the number of modes that have to be considered is low, just one or two for each bending plane, and it supposes an important improvement in the application of the RCSA to the calculation of stability diagrams. The predictions of this new method have been verified experimentally.

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Gagnol, Vincent, Belhassen C. Bouzgarrou, Pascal Ray, and Christian Barra. "Stability-Based Spindle Design Optimization." Journal of Manufacturing Science and Engineering 129, no. 2 (2006): 407–15. http://dx.doi.org/10.1115/1.2673400.

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Prediction of stable cutting regions is a critical requirement for high-speed milling operations. These predictions are generally made using frequency-response measurements of the tool-holder-spindle set obtained from a nonrotating spindle. However, significant changes in system dynamics occur during high-speed rotation. In this paper, a dynamic high-speed spindle-bearing system model is elaborated on the basis of rotor dynamics prediction and readjusted on the basis of experimental modal identification. The dependency of dynamic behavior on speed range is then investigated and determined with accuracy. Dedicated experiments are carried out in order to confirm model results. They show that dynamic effects due to high rotational speed and elastic deformations, such as gyroscopic coupling and spin softening, have a significant influence on spindle behavior. By integrating the modeled speed-dependent spindle transfer function in the chatter vibration stability approach of Altintas and Budak (1995, CIRPS Ann, 44(1), pp. 357–362), a new dynamic stability lobe diagram is predicted. Significant changes are observed in the stability limits constructed using the proposed approach and allow accurate prediction of cutting conditions to be established. Finally, optimization studies are performed on spindle design parameters in order to obtain a chatter vibration-free cutting operation at the desired speed and depth of cut for a given cutter.

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Li, Feng, Fang Yu Peng, Yong Wang, Rong Yan, and Bin Li. "Optimization of Parameters of Aircraft Landing Gear with Orthogonal Turn-Milling Based on GRA-PSO Algorithm." Advanced Materials Research 852 (January 2014): 730–34. http://dx.doi.org/10.4028/www.scientific.net/amr.852.730.

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In the light of the characteristic of 300M ultra high strength steel and the feature of orthogonal turn-milling machining,an optimization model of orthogonal turn-millng machining parameters is consisted of maximum tool life,minimum surface roughness and maximum productivity. Based on multi-objective optimazation algorithm which is applied in coupling particle swarm optimization algorithm and gray relevancy analysis,it can achieve the purpose which is above mentioned. By introducing the chatter stability lobe diagram of aircraft landing gear with orthogonal turn-milling which is conformed with DMG turn-milling machine tool,it can optimize the parameters of the orthogonal turn-milling machining of the aircraft landing gear with high efficiency and good quality.

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Zhao, Yong Sheng, Ri Qing Dong, Zhi Feng Liu, and Tie Neng Guo. "Identification of Dynamical Contact Parameters for Spindle-Tool Holder Interface Based on the Receptance Coupling Substructure Approach." Advanced Materials Research 287-290 (July 2011): 2185–90. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.2185.

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It is very crucial to accurately identify the parameters of contact dynamics in predicting the chatter stability of spindle–tool holder assemblies in machining centers. Fast and accurate identification of contact dynamics in spindle–tool holder assembly has become an important issue in the recent years. In this paper, the receptance coupling substructure approach is employed for identification the stiffness and damping of the interface in a simple manner, in which the frequency response function of the tool holder is derived from the Timoshenko beam finite elements model. A BT 50 type tool holder is adopted as an application example of the method. Although this study focuses on the contact dynamics at the spindle–tool holder interfaces of the assembly, the approach might be used for identifying the dynamical parameters of other critical interface.

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Zhao, Wu, Zhan Qi Hu, and Dan Huang. "Global Stability Analysis on Combination Self-Excited Vibration of BTA Deep-Hole Boring Rotor Materials." Key Engineering Materials 667 (October 2015): 75–81. http://dx.doi.org/10.4028/www.scientific.net/kem.667.75.

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Cr, Ni, Mo, V exist in materials of high, medium and low pressure turbine rotor. Its composition contains higher carbon content, so leads to poor hardenability. Shear characteristics of martensite phase transformation is caused by a large number of micro defects inside crystal of microstructure in rotor during the service status. Martensite phase transformation is by strengthening because of plastic deformation in cutting process. Mechanical properties and phase transformation plasticity in cutting process show that rotor is hard machining material. Plastic deformation aggravates tool wear, and leads to an increased cutting force; hard points of uneven material internal organization lead to fluctuation of cutting force, and induced cutting chatter. During the course of machining critical or ultra-supercritical rotor, boring bar becomes a flexible system surrounded by rotating stirred vortex cutting fluid inside and outside it. BTA processing system is in a complicated hydraulic-solid coupling environment. Whether or not BTA deep hole boring processing system is stable, the essence is converted into estimating dynamic stability of BTA boring bar coupled fluid--solid with multi-physics environment. The system will be triggered cutting chatter, fluid flutter and self-excited vibration combination. This paper establishes nonlinear mathematical physics model on BTA deep hole processing system. The perturbation equation and Lyapunov function of BTA system are obtained, through introducing the stable Rumjantsev part variables analysis theory. Based on stability characteristic under the significance of Lyapunov, the constraint condition undisturbed stability is gotten and the global bifurcation analysis is finished. Hyperbolic periodic orbit and heteroclinic connection are found throughout the entire phase space of Hamiltonian system. The bifurcation condition on quadratic heteroclinic is acquired, by analyzing intersection relationship between hyperbolic stable manifold and its unstable manifold of Poincare mapping. The intersection critical conditions are shown on hyperbolic fixed stable manifold and its unstable manifold, by using computer numerical simulation to draw 3-D surface relationship among resonant frequency, cutting fluids flow velocity and the radius of free surface. The result could provide a reference on multi-machining parameters optimization for BTA deep hole boring process practical production.

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Jakimowicz, Dagmara, Sebastien Mouz, Jolanta Zakrzewska-Czerwińska, and Keith F. Chater. "Developmental Control of a parAB Promoter Leads to Formation of Sporulation-Associated ParB Complexes in Streptomyces coelicolor." Journal of Bacteriology 188, no. 5 (2006): 1710–20. http://dx.doi.org/10.1128/jb.188.5.1710-1720.2006.

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ABSTRACT The Streptomyces coelicolor partitioning protein ParB binds to numerous parS sites in the oriC-proximal part of the linear chromosome. ParB binding results in the formation of large complexes, which behave differentially during the complex life cycle (D. Jakimowicz, B. Gust, J. Zakrzewska-Czerwinska, and K. F. Chater, J. Bacteriol. 187:3572-3580, 2005). Here we have analyzed the transcriptional regulation that underpins this developmentally specific behavior. Analysis of promoter mutations showed that the irregularly spaced complexes present in vegetative hyphae are dependent on the constitutive parABp 1 promoter, while sporulation-specific induction of the promoter parABp 2 is required for the assembly of arrays of ParB complexes in aerial hyphae and thus is necessary for efficient chromosome segregation. Expression from parABp 2 depended absolutely on two sporulation regulatory genes, whiA and whiB, and partially on two others, whiH and whiI, all four of which are needed for sporulation septation. Because of this pattern of dependence, we investigated the transcription of these four whi genes in whiA and whiB mutants, revealing significant regulatory interplay between whiA and whiB. A strain in which sporulation septation (but not vegetative septation) was blocked by mutation of a sporulation-specific promoter of ftsZ showed close to wild-type induction of parABp 2 and formed fairly regular ParB-enhanced green fluorescent protein foci in aerial hyphae, ruling out strong morphological coupling or checkpoint regulation between septation and DNA partitioning during sporulation. A model for developmental regulation of parABp 2 expression is presented.

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Cen, Lejun, Shreyes N. Melkote, James Castle, and Howard Appelman. "A Method for Mode Coupling Chatter Detection and Suppression in Robotic Milling." Journal of Manufacturing Science and Engineering 140, no. 8 (2018). http://dx.doi.org/10.1115/1.4040161.

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A new method for online chatter detection and suppression in robotic milling is presented. To compute the chatter stability of robotic milling along a curvilinear tool path characterized by significant variation in robot arm configuration and cutting conditions, the tool path is partitioned into small sections such that the dynamic stability characteristics of the robot can be assumed to be constant within each section. A methodology to determine the appropriate section length is proposed. The instantaneous cutting force-induced dynamic strain signal is measured using a wireless piezoelectric thin-film polymer (polyvinyldene fluoride (PVDF))-based sensor system, and a discrete wavelet transform (DWT)-based online chatter detection algorithm and chatter suppression strategy are developed and experimentally evaluated. The proposed chatter detection algorithm is shown to be capable of recognizing the onset of chatter while the chatter suppression strategy is found to be effective in minimizing chatter during robotic milling.

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Yang, Chong, Lu Dace, and Wang Hongli. "Design of rotational inverted pendulum control based on second-order sliding mode." International Journal of Electrical Engineering & Education, February 27, 2021, 002072092098848. http://dx.doi.org/10.1177/0020720920988488.

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Rotational Inverted Pendulum is a typical nonlinear, unstable and strong coupling system. How to design a control system to restore the equilibrium state quickly and stably is a problem worth studying. High order super twisting sliding mode system has the advantages of traditional sliding mode control system. Super twisting system can elimination control chatter due to the discontinuities of control variable which contain in traditional sliding mode system. The super twisting system is designed. The saturation function replaces the sign function in the super twisting control function to improve the smoothness of the control variable. The simulation shows that this design has excellent precision. Inverted pendulum has smaller movement stroke than traditional super twisting system. Control chatter is also smaller than traditional super twisting system.

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Altintas, Yusuf, Gabor Stepan, Erhan Budak, Tony Schmitz, and Zekai Murat Kilic. "Chatter Stability of Machining Operations." Journal of Manufacturing Science and Engineering 142, no. 11 (2020). http://dx.doi.org/10.1115/1.4047391.

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Abstract This paper reviews the dynamics of machining and chatter stability research since the first stability laws were introduced by Tlusty and Tobias in the 1950s. The paper aims to introduce the fundamentals of dynamic machining and chatter stability, as well as the state of the art and research challenges, to readers who are new to the area. First, the unified dynamic models of mode coupling and regenerative chatter are introduced. The chatter stability laws in both the frequency and time domains are presented. The dynamic models of intermittent cutting, such as milling, are presented and their stability solutions are derived by considering the time-periodic behavior. The complexities contributed by highly intermittent cutting, which leads to additional stability pockets, and the contribution of the tool's flank face to process damping are explained. The stability of parallel machining operations is explained. The design of variable pitch and serrated cutting tools to suppress chatter is presented. The paper concludes with current challenges in chatter stability of machining which remains to be the main obstacle in increasing the productivity and quality of manufactured parts.

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Yu, S. D., and V. Shah. "Theoretical and Experimental Studies of Chatter in Turning for Uniform and Stepped Workpieces." Journal of Vibration and Acoustics 130, no. 6 (2008). http://dx.doi.org/10.1115/1.2948384.

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This paper presents a method for predicting regenerative chatter onset conditions for uniform and stepped workpieces. The lateral deflections of flexible workpieces are modeled using the Timoshenko beam theory and three-node beam finite elements. The modal summation method is employed in conjunction with an adaptive remeshing scheme to determine the varying natural frequencies and varying mode shapes of workpieces during a cutting process, and to reduce the system equations of motion in terms of nodal variables to coupled equations of motion in terms of the modal coordinates. Various simulations were conducted and presented in this paper for understanding the gyroscopic and cross-coupling effect, and effects of other system and cutting process parameters on chatter onset conditions. Six experiments were carried out on an engine lathe for three uniform and three stepped workpieces to verify the theoretical chatter onset conditions. Good agreement in chatter onset conditions was observed between the simulations and the experiments.

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Zhao, Huyue, and Kornel F. Ehmann. "Stability Analysis of Chatter in Tandem Rolling Mills—Part 1: Single- and Multi-Stand Negative Damping Effect." Journal of Manufacturing Science and Engineering 135, no. 3 (2013). http://dx.doi.org/10.1115/1.4024032.

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Many different modes of chatter in rolling and their possible causes have been identified after years of research, yet no clear and definite theory of their mechanics has been fully established and accepted. In this two-part paper, stability of tandem mills is investigated. In Part 1, state-space models of single- and multi-stand chatter are formulated in a rigorous and comprehensive mathematical form. Then, the stability of the rolling system is investigated in the sense of the single- and multi-stand negative damping effects. First, a single-stand chatter model in state-space representation is proposed by coupling a dynamic rolling process model with a structural model for the mill stand. Subsequently, a multi-stand chatter model is developed by incorporating the inter-stand tension variations and the time delay effect of the strip transportation based on the single-stand chatter model. Stability criteria are proposed and stability analyses are performed to create corresponding stability charts in terms of the single- and multi-stand negative damping mechanism through numerical simulations. Particularly, the effect of friction conditions on chatter is examined and an explanation is given for the existence of an optimum friction condition. In Part 2, the regenerative effect and resulting instabilities are examined. Suitable stability criteria for each mechanism are established and stability charts are demonstrated in terms of relevant rolling process parameters.

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Yang, Xu, and Chao-nan Tong. "Coupling Dynamic Model and Control of Chatter in Cold Rolling." Journal of Dynamic Systems, Measurement, and Control 134, no. 4 (2012). http://dx.doi.org/10.1115/1.4005498.

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The dynamic model of 4-h mill, which couples with the rolling process model, the mill roll stand structure model, and the hydraulic servo system model, is built by analyzing the vibration process of cold rolling. By linearization, the multiple input multiple output linear transfer function matrix model of single stand 4-h cold mill system is obtained. With the consideration of strip quality, the model of strip thickness control system is established in a simplified form. Meanwhile, the robust controller based on quantitative feedback theory is designed for the gauge control model. A comparison with PID controller shows that the controller has better disturbance attenuation performance for parameter uncertainty and external disturbance.

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Lu, Xiaohong, Zhenyuan Jia, Shengqian Liu, Kun Yang, Yixuan Feng, and Steven Y. Liang. "Chatter Stability of Micro-Milling by Considering the Centrifugal Force and Gyroscopic Effect of the Spindle." Journal of Manufacturing Science and Engineering 141, no. 11 (2019). http://dx.doi.org/10.1115/1.4044520.

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Abstract In the micro-milling process, the minimization of tool chatter is critical for good surface finish quality. The analysis of chatter requires an understanding of the milling tool as well as the dynamics of milling system structure. Frequency response function (FRF) at the micro-milling tool point reflects dynamic behavior of the whole micro-milling machine–spindle–tool system. However, the tool point FRF of micro-milling cannot be obtained directly through the hammering test. To solve the problem, the authors get the FRF of the spindle system based on the rotating Timoshenko beam theory and the receptance coupling substructure analysis (RCSA), and the bearing characteristics are added into the spindle model through structural modification. Then, the centrifugal force and gyroscopic effect caused by the high-speed rotation of the micro-milling spindle are considered to better simulate the real scenario and increase the accuracy of modal parameters. The method has general usage and can be applied to all the micro-milling tools under which only the spindle dimension, bearing characteristics, and contact parameters need to be changed.

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Allison, Timothy C., and Klaus Brun. "Testing and Modeling of an Acoustic Instability in Pilot-Operated Pressure Relief Valves." Journal of Engineering for Gas Turbines and Power 138, no. 5 (2015). http://dx.doi.org/10.1115/1.4031623.

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Pressure relief valves (PRVs) are included as an essential element of many compressor piping systems in order to prevent overpressurization and also to minimize the loss of process gas during relief events. Failure of the valve to operate properly can result in excessive quantities of vented gas and/or catastrophic failure of the piping system. Several mechanisms for chatter and instability have been previously identified for spring-loaded relief valves, but pilot-operated relief valves are widely considered to be stable. In this paper, pilot-operated PRVs are shown to be susceptible to a dynamic instability under certain conditions where valve dynamics couple with upstream piping acoustics. This self-exciting instability can cause severe oscillations of the valve piston, damaging the valve seat, preventing resealing, and possibly causing damage to attached piping. Two case studies are presented, which show damaging unstable oscillations in a field installation and a blowdown rig, and a methodology is presented for modeling the instability by coupling a valve dynamic model with a 1D transient fluid dynamics simulation code. Modeling results are compared with measured stable and unstable operation in a blowdown rig to show that the modeling approach accurately predicts the observed behaviors.

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Duan, Zhenjing, Changhe Li, Wenfeng Ding, et al. "Milling Force Model for Aviation Aluminum Alloy: Academic Insight and Perspective Analysis." Chinese Journal of Mechanical Engineering 34, no. 1 (2021). http://dx.doi.org/10.1186/s10033-021-00536-9.

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AbstractAluminum alloy is the main structural material of aircraft, launch vehicle, spaceship, and space station and is processed by milling. However, tool wear and vibration are the bottlenecks in the milling process of aviation aluminum alloy. The machining accuracy and surface quality of aluminum alloy milling depend on the cutting parameters, material mechanical properties, machine tools, and other parameters. In particular, milling force is the crucial factor to determine material removal and workpiece surface integrity. However, establishing the prediction model of milling force is important and difficult because milling force is the result of multiparameter coupling of process system. The research progress of cutting force model is reviewed from three modeling methods: empirical model, finite element simulation, and instantaneous milling force model. The problems of cutting force modeling are also determined. In view of these problems, the future work direction is proposed in the following four aspects: (1) high-speed milling is adopted for the thin-walled structure of large aviation with large cutting depth, which easily produces high residual stress. The residual stress should be analyzed under this particular condition. (2) Multiple factors (e.g., eccentric swing milling parameters, lubrication conditions, tools, tool and workpiece deformation, and size effect) should be considered comprehensively when modeling instantaneous milling forces, especially for micro milling and complex surface machining. (3) The database of milling force model, including the corresponding workpiece materials, working condition, cutting tools (geometric figures and coatings), and other parameters, should be established. (4) The effect of chatter on the prediction accuracy of milling force cannot be ignored in thin-walled workpiece milling. (5) The cutting force of aviation aluminum alloy milling under the condition of minimum quantity lubrication (mql) and nanofluid mql should be predicted.

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Journal articles on the topic 'Mode coupling chatter'

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