• 한국기계가공학회지
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• 제18권7호
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• pp.1-7
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• 2019

A chatter lobe analysis is frequently used to look at the chatter state. Even if there is a lot of research on chatter, chatter lobe characteristics are not well defined. In this study, the chatter lobe behavior according to several variables of vibration mode is verified for further clarity. The dynamic variables of the chatter model are defined and their behaviors on chatter lobe boundary are analyzed in detail. In this sense, the chatter model with 2-DOF (2-DOF) was used to analyze chatter stability characteristics. The discussed results are satisfying and these can be used for the prediction of chatter existence in machining processes of 2-DOF systems in several revolution range. These analyses indicate a better agreement for predicting an appropriate stability lobe over a wide detailed range of critical depths of cut in machining operation. The results allow an excellent prediction of chatter according to various static and dynamic variables in machining states. The behavior of chatter dynamic variables in machining were also discussed in detail. All these results can also be applied to other machining processes by establishing a chatter model in a 2-DOF system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.261-264
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• 2000

This paper presents a method to identify the on-set of chatter by using the chatter frequency-spindle speed diagram for a milling spindle-workpiece system in face milling process. To this purpose, the eigenvalue problem approach using frequency response function is adopted for predicting both the chatter condition and chatter frequency. The chatter frequency -spindle speed diagram for various conditions is investigated throughout simulation and experiment to diagnose the chatter. The simulation and experimental results show that the chatter frequency-spindle speed diagram is useful for diagnosis of the on-set of chatter vibration.

• 한국정밀공학회지
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• 제8권3호
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• pp.73-81
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• 1991

There have been many studies on chatter vibration in machining but there seems to be no regulations to decide the commencing point of chatter objectively. The development of an objective method which can estimate and detect chatter commencement is very much in need for automatic manufacturing systems, dynamic performance tests for machine tools, so on. In this study, therefore, the estimation and the in-process detection of chatter have been experi- mentally investigated for the turning process. As a result, the commencing point of chatter can be decided from the behavior of the maximum amplitude of the dynamic component of cutting force, where the maximum amplitude is suddenly increasing with the chatter commencement. Then the commencing point of chatter can be estimated practically by this method before the occurrence of excessive vibration. Also, it is possible to detect the occurence of chatter vibration through the in-process measurement, by monitoring the maximum amplitude of the dynamic component of cutting force.

• 한국정밀공학회지
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• 제32권1호
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• pp.9-16
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• 2015

The machining-chatter stands for a sudden relative vibration appeared between a material and a tool while processing with a machine. This chatter is key factor that seriously affects the quality of processed materials as well as being a factor which causes serious damages to the tool and the machine. This study is related to the monitoring and smart control of chatter problem that can compensate machining-chatter faster and produce processed goods with more precision by autonomous compensation. The above-mentioned machining-chatter compensator includes the chatter vibration sensor and the chatter compensator that estimates the compensation value according to the sensor detecting the chatter vibration of machine-tool and the chatter vibration detected from the sensor while having a feature of being organized by interlocking with the machine-tool controller.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.28-32
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• 1995

Bacause the chatter vibration is a main factor to damage on the quality and integrity, The cure is required peticurity in cykinderical plunge grinding. The chatter vibration relatied with wheel speed, workpiece and infeed rate. Therefore, we expressed more credible normal signal and chatter signal Pattern in accrdiance with wheel speed and acquired RMS signal of the accelerrometer. In thos study, after finding the chatter pattern, we applied two parameters, standard deviation and Kurtosis, to Neural Network.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.977-981
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• 1997

Because the chatter vibration is a main factor to damage on the quality, The cure is require peticually in cylinderical plunge grinding. The chatter vibration is with wheel speed, workpiece speed and infreed rate. Therefore, in this study, we expressed more credible chatter frequency in accordiance with wheel speed by FFT after accereleration sensing.

• 대한기계학회논문집
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• 제18권7호
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• pp.1618-1631
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• 1994

In this paper, in-process chatter detection methodology which utilizes nondimensional characteristic variables is introduced. To obtain nondimensional chatter detection indexes which are constant regardless of the cutting conditions during machining with the same tool and workpiece material, both the cutting forces and accelerations are measured and processed in time and frequency domain. The indexes are calculated from the present and past value of the acceleration and cutting force signals in time and frequency domain. The chatter is identified when these chatter detection indexes are bigger than the threshold which is decided by preliminary experiments. The experiment shows that these indexes works very well in-process chatter detection.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.745-750
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• 2014

The chatter vibration in the machining process plays bad role in machining quality such as high roughness as well as tool life and machine failure. And the grinding process under this risk in the fully automated factory is exposed to the unexpected mass machining quality problem. Studying the vibration signal of the hub bearing grinding process, the reason of chatter vibration was explained with the specific machining pattern of chatter. And this study suggests the chatter detecting method in the production line, which is monitoring the peak acceleration level around the natural frequencies of the specimen, and calculating kurtosis value by assuming the chatter is related to the resonance of the specimen. The suggested method was applied to the vehicle hub bearing grinding process and proved good to detecting the chatter induced machining quality problem.

• 대한기계학회논문집
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• 제9권6호
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• pp.706-713
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• 1985

본 논문에서는 연삭공정에서 채터의 진폭이 충분히 증가하면 숫돌차와 공작물 의 접촉이 더이상 유지되지 못하고 서로 떨어지게 되는 소위 접촉 이탈 현상에 의한 비선형 채터에 관한 연구를 수행하였다.비선형 요소인 비대칭 게인 (asymmetrical gain)을 사용하여 비선형 채터루우프를 유도 하였으며 기술 함수 방법(describing function method)에 의해 복소수 평면에서의 해석을 수행 하였다.또한 수치 시뮬레 이션에 의한 시간 영역에서의 해석을 수행 하였으며 그 결과를 서로 비교하였다. 이 와같은 연구를 통하여 그 비선형 효과에 의해 발생되는 연삭 채터의 특징적 현상을 구 명하였다.

• 한국생산제조학회지
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• 제23권3호
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• pp.273-278
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• 2014

This study presents a chatter vibration avoidance program for the milling process. Chatter vibration has a negative effect on workpieces and spindle-tools. When chatter vibration occurs, the cutting tool is loaded dynamically, a chatter pattern is generated on the workpiece, and the tool life is reduced. The developed program is composed of various modules such as an FFT analyzer, an impact test analyzer, a chatter vibration indicator, and a spindle speed recommender. The proposed program is verified using an AISI D2 cutting experiment in milling process. The effect of chatter vibration on the machining condition can be simulated by the suggested method, and successfully exploited to avoid chatter vibration.