• 한국정밀공학회지
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• 제21권3호
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• pp.22-29
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• 2004

Runout causes severe differences among cutting force waveforms due to changes of rotational radii. Thus a runout model must be included in a cutting force model to simulate cutting force accurately. In this paper, a runout modeling method and a measurement method using a dialgauge were developed, which were easy to apply. To calculate runout parameters, a computer program algorithm which obtained runout parameters from measurement values was developed. Cutting force waveforms simulated from cutting force model considering runout effect and measured from experiments had good agreements for their wave size and order.

• 한국정밀공학회지
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• 제17권1호
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• pp.171-178
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• 2000

In this study, an indirect method to estimate the setup runout of a ball-end mill from cutting force signal is proposed. This runout makes cutting forces of each tooth of the milling cutter unequal. By transforming the cutting force model from time domain to frequency domain through time-convolution theorem, the magnitude and phase angle of runout can be explicitly expressed with material constants, cutting conditions, and force signal. The static setup runout can be obtained by extrapolating estimated effective runout, which is independent of feedrate but decreases linearly with increase in axial depth of cut. The setup runout estimated by slot cutting experiments, shows good agreement with the measured one.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.151-156
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• 1995

This paper presents a methodology for real-time detecting and identifying the runout geometry of an end mill. Cutter runout is a common but undesirable phenomenon in multi-tooth machining such as end-milling process because it introduces variable chip loading to insert which results in a accelerated tool wear,amplification of force variation and hence enlargement vibration amplitude. Form understanding of chip load change kinematics, the analytical sutting force model was formulated as the angular domain convolution of three dynamic cutting force component functions. By virtue of the convolution integration property, the frequency domain expression of the total cutting forces can be given as the algebraic multiplication of the Fourier transforms of the local cutting forces and the chip width density of the cutter. Experimental study are presented to validata the analytical model. This study provides the in-process monitoring and compensation of dynamic cutter runout to improve machining tolerance tolerance and surface quality for industriql application.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.995-1000
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• 2000

In this paper. a mechanistic model is first constructed to predict three-dimensional cutting forces, and the uncut chip th thickness is calculated by following the movements of the position of the center of a cutter, which varies with the nominal feed, cutter deflection and runout. For general implementation to a real machining, this paper presents the method that determines constant cutting force coefficients, irrespective of the cutting conditions or cutter rotation angles. In addition, this study presents the approach which estimates runout-related parameters. the runout offset and its location angle, using only one measurement of cutting forces. For more accurate cutting force predictions, the size effect has to be considered in the cutting force model. In this paper, two approximate methods are suggested since the strict approach is practically impossible due to a measurement problem. The size effect is individually considered for narrow and wide cuts.

• 한국생산제조학회지
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• 제7권2호
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• pp.91-99
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• 1998

This paper presents a methodology for identifying the cutter runout geometry in end milling process. Cutter runout is common but undesirable phenomenon in multi-tooth machining because it introduces variable chip loading to insert which results in a accelerated tool wear. amplification of force variation and hence enlargement vibration amplitude From understanding of chip load change kinematics, the analytical cutting force convolution model was formulated as the angular domain convolution model was formulated as the angular domain convolution of three dynamic cutting force component functions. By virtue of the convolution integration property, the frequency domain expression of the local cutting forces and the chip width density of the cutter. Experimental study is presented to validate the analytical model. This study provides the in-process monitoring and compensation of dynamic cutter runout to improve machining tolerance and surface quality for industrial application.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.788-793
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• 1997

The surface,generated by end milling operation, is deteriorated by tool runout,vibration,friction,tool deflection, etc. In many source,deflection of tool affects to surfave accuracy. To develop a surface accracy model,method for the prediction of the topography of machined surfaces has been developed based on models of machine tool kinematics and cutting tool geometry. This model accounts for not only the ideal geometrical surface, but also the deflection of tool resulted in cutting force. For the more accurate prediction of cutting force,flexible end mill model is used to simulate cutting process. Compute simu;ation have shown the feasibility of the surface generation system.

• 한국정밀공학회지
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• 제16권4호통권97호
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• pp.229-236
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• 1999

The surface, generated by end milling operation, is deteriorated by tool runout, vibration, tool wear and tool deflection, etc. Among them, the effect of tool deflection on surface accuracy is analyzed. Surface generation model for the prediction of the topography of machined srufaces has been developed based on cutting mechanism and cutting tool geometry. This model accounts for not only the ideal geometrical surface, but also the deflection of tool due to cutting force. For the more accurate prediction of cutting force, flexible end mill model is used to simulate cutting process. Computer simulation has shown the feasibility of the surface generation system. Using developed simulation system, the relations between the shape of end mill and cutting conditions are analyzed.

• 한국정밀공학회지
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• 제18권3호
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• pp.195-204
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• 2001

Virtual computer numerical control(VCNC) arises from the concept that one can experience pseudo-real machining with a computer-numerically-controlled(CNC) machine before actually cutting an object. To achieve accurate VCNC, it is important to determine abnormal behavior, such as chatter, before cutting. Detecting chatter requires an understanding of the dynamic cutting force model. In general, the cutting process is a closed loop system that consists of structural and cutting dynamics. Machining instability, namely chatter, results from the interaction between these two dynamics. Several previous reports have predicted stability for a single path, using a simple cutting force model without tool runout and penetration effects. This study considers both tool runout and penetration effects, using experimental modal analysis, to obtain more accurate predictions. The machining stability in the corner cut, which is a typical transient cut, was assessed from an evaluation of the cutting configurations at the corner.

• 대한토목학회논문집
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• 제32권3B호
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• pp.193-201
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• 2012

지난 10년이래 집중강우에 의해서 유발된 토석류가 우리나라에서 현저히 발생하고 있다. 그로 인해 산지유역에서 토석류는 가장 위험한 자연재해 중 하나가 되고 있다. 토석류 위험지도와 방재 기술을 개발하기 위해서 먼저 이해해야 하고 정확히 예측해야 하는 것 중 하나는 발생한 토석류의 이동거리이다. 단순하고 적용범위가 넓은 sled 모형에 근거해서, 이 연구에서는 현장조사를 통해 구한 토석류 자료를 이용하여 토석류의 수평이동거리(L)에 대한 토석류 시작점과 퇴적점의 표고차(H) 비로 정의되어 이동성을 나타내는 토석류의 순효율을 산정하였다. 2002년 이후 현재까지 확보된 국내 238개의 토석류 현장 자료를 분석한 결과 한국 토석류의 순효율 대푯값은 4.3인 것으로 나타났다. 가장 많은 토석류가 발생하는 강원지역의 경우 강릉과 평창지역보다는 인제지역의 토석류가 상대적으로 표고차에 비해 이동거리가 큰 것으로 나타났다. 국내 토석류를 중부지역과 남부지역으로 나눠 분석한 결과 두 지역 모두 토석류의 전반적인 순효율 분포는 유사한 것으로 나타났다. 가용한 토석류 퇴적조건 적용과 항공사진 분석을 통해 산정하는 방법은 토석류의 순효율을 과대 산정하는 것으로 나타났다. 이 방법을 적용하기 위해서는 우리나라 토석류에 적합한 퇴적조건을 도출하는 연구가 필요한 것으로 나타났다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.49-54
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• 1994

A dynamic model for the cutting process in the end milling process is developed. This model, which describes the dynamic response of the end mill, the chip load geometry including tool runout, the dependence of the cutting forces on the chip load, is used to predict the dynamic cutting force during the end milling process. In order to predict accurately cutting forces and tool vibration, the model, which uses instantaneous specific cutting force, includes both regenerative effect and penetration effect. The model is verified through comparisons of model predicted cutting force with measured cutting forces obtained from machining experiments.