• 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.

• 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.

• 대한기계학회논문집A
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• 제28권1호
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• pp.70-78
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• 2004

This paper presents study of efficiency of wavelet transformation for on-line chatter detection during hard fuming process. From comparison with other time series and statistical methods such as fast fourier transformation (FFT), Kurtosis and standard deviation (STD), wavelet transform is better than others in on-line chatter detection. With using wavelet function with pseudo frequency corresponding to chatter frequency, chatter could be detected more sensitively. And for both force signal from dynamometer and displacement signal from capacitance type cylindrical sensor (CCS), wavelet transform with DB2 function on level 4 could be well used for chatter detection in hard turning process.

• 한국공작기계학회논문집
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• 제10권3호
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• pp.12-18
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• 2001

Frequency domain has been used to detect chatter vibration and to decide commencing point of chatter for the milling processes. For this, power spectrum of accelerations signal is analyzed in the frequency domain. Also, the power spectrum and surface roughness are measured, compared, and evaluated according to the depth of cut by experimental works. As a results, it is known that the commencing point of chatter can be decided the behavior of the maximum amplitude of the power spectrum of acceleration signal and there is a correlation between the power spectrum of acceleration signal and the surface roughness. In conclusion, the power spectrum of acceleration signal can be used as a useful information for detec-tion and estimation of chatter vibration in machining.

• 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.

• 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.

• 한국공작기계학회논문집
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• 제10권4호
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• pp.76-83
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• 2001

In this study, the static and dynamic characteristics of turning process was modelled and the analytic realization of regen-erative chatter mechanism was discussed. In this regard, we have discussed on the comparative assessment of recursive times series modeling algorithms that can represent the machining process and detect the abnormal machining behaviors in precision turning operation. In this study, simulation and experimental work were performed to show the malfunction behaviors. For this purpose, new Recursive Extended Instrument Variable Method(REIVM) was adopted for the on-line system identification and monitoring of a machining process. Also, we can apply REIVE algorithms in real process for the detection of chatter frequency and dynamic property and analyze the stability lobe of the system by changing a parameter of cutting dynamics in regenerative chatter mechanics, if it is stable or unstable, Also, The stability lobe of chatter was analysed.

• 한국정밀공학회지
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• 제9권3호
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• pp.117-121
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• 1992

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, and so on. In this study, an approach for in-process monitoring and for deciding commencing point of the chatter vibration using the frequency band-energy method was proposed. From this method, in-process monitoring system for detection the chatter vibration was developed, and investigated its practical possibility. As a result, it is shown by experiments that the chatter vibtation can be detected accurately. Since the changing pattern of the signal energy in certain frequency band during chattering is seldom affected by the variation of cutting conditions, if adequate pre-measures are taken, this method can be widely used in most machining processes.

• 한국생산제조학회지
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• 제19권3호
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• pp.340-345
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• 2010

This paper presents the chatter stability lobes of high speed spindle of five-axis machine tools. Using a FEM, we obtained the frequency response function of a spindle and the stability lobes for evaluation of chatter. In addition, this paper suggest FRF using by FEM for the prediction of chatter stable region and critical cutting depth. Therefore, critical cutting depth of is 1.3586mm and X, Y direction's chatter frequency is 901Hz and 900Hz, respectively.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1996년도 추계학술대회 논문
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• pp.85-90
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• 1996

In order to detect and suppress chatter in turning processes a stability control methodology was studied through manipulation of spindle speeds regarding to chatter frequencies. The chatter frequency was identified by monitoring and signal processing of sound pressure during turning on a lathe. The stability control methodology can select stable spindle speeds without knowing a prior knowledge of machine compliances and cutting dynamics. Teliability of the developed stability control methodology was verified through turning experiments on an engine lathe. Experimental results show that a microphone is an excellent sensor for chatter detection and control