• 복식문화연구
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• 제17권3호
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• pp.499-511
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• 2009

As the demand of the consumer for high-sense clothing, relation with materials is becoming important even in clothing construction. Especially, the cutting angle of materials is becoming an crucial element in the formation of silhouette, and drape of Hem line, of skirts. Accordingly, in this study, Hem line shapes between real clothing and 3D virtual clothing of "i-Designer" were analyzed by manufacturing semi-flare skirts of polyester 100% according to a cutting angle, and the results are as follows. As a result of comparison of silhouette between the real clothing and the virtual clothing, the real and the virtual have a similar feeling regardless of a cutting angle. In case of drape shapes, both the front and the lateral side were represented in almost similar shapes. The back side, however, the real and the virtual showed a great difference in case of grain direction. And in the whole silhouette, the real and the virtual were represented similarly. It could be known that with regard to Hem-line drape shapes between the real clothing and the virtual according to a cutting angle, the real clothing is represented in a location farther from the body than the virtual clothing and, the location or number of node was similarly showed in the real and the virtual.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.639-642
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• 2000

• International Journal of Precision Engineering and Manufacturing
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• 제6권3호
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• pp.24-28
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• 2005

Stress state of chip formation zone is one of the main problems in metal cutting mechanics. In two-dimensional case this process is usually considered as consistent shears of work material along one of several shear surfaces, separating chip from workpiece. These shear planes are assumed to be trajectories of maximum shear stress forming corresponding slip-line field. This paper suggests a new approach to the constriction of slip-line field, which implies uniform compression in chip formation zone. Based on the given model it has been found that imaginary shear line in orthogonal cutting is close to the trajectory of maximum normal stress and the problem about its determination has been considered as well. It has been shown that there is a second central slip-line field inside chip, which corresponds well to experimental data about stress distribution on tool rake face and tool-chip contact length. The suggested model would be useful in understanding mechanistic problems in machining.

• 한국정밀공학회지
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• 제5권1호
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• pp.84-93
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• 1988

The on-line detection of the chip flow is one of the most important technologies in com- pletly automatic operation of machine tool, such as FMS and Unmanned Factories. This problem has been studied by many researchers, however, it is not solved as yet. For the recognition of chip flow in this study, the dynamic cutting force components due to the chip breaking were measured by dynamometer of piezo-electric type, and the frequency components of cutting force were also analyzed. From the measured results, the effect of cutting conditions and tool geometry on the dynamic cutting force component and chip formation were investigated in addition to the relationships between frequency of chip breaking (fB) and side serrated crack (fC) of chip. As a result, the following conclusions were obtaianed. 1) The chip formations have a large effect on the dynamic cutting force components. When chip breaking takes place, the dynamic cutting force component greatly increases, and the peridoic components appear, which correspond to maximum peak- frequency. 2) The crater wear of tool has a good effect on the chip control causing the chiup to be formed as upward-curl shape. In this case, the dymamic cutting force component greatly increases also 3) fB and fC of chip are closely corelated, and fC of chips has a large effect on the change of the situation of chip flow and dynamic cutting force component. 4) Under wide cutting conditions, the limit value (1.0 kgf) of dynamic cutting force component exists between the broken and continuous chips. Accordingly, this value is suitable for recognition of chip flow in on-line control of the cutting process.

• 한국공간구조학회논문집
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• 제12권1호
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• pp.109-119
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• 2012

막 구조물은 일반적인 설계와는 달리 형상해석, 응력변형해석 및 재단도 과정을 수행하여야만 설계가 가능하다. 처음 두 과정과는 달리 재단은 3차원 곡면을 최소 오차를 가진 평면 스트립을 형성하는 과정이다. 경제적인 이유로 재단 선은 주로 측지선을 이용하여 작성된다. 그러나 일반적으로 측지선은 초기 형상탐색에서 구성된 삼각형 요소의 정보에서 추출됨으로 부드러운 곡선이 아니며, 불규칙한 직선이다. 그러므로 어떻게 불규칙한 직선을 곡선으로 표현할 것인가가 중요하다. 따라서 본 연구에서는 스플라인 함수를 이용한 보간 방법을 재단도 생성에 적용하였다. 이를 위해서 삼차 스플라인 함수, B-스플라인 함수 및 최소자승 스플라인 함수의 세 가지 경우에 대해서 고찰하고, 단순 모델 및 카테나리 모델을 대상으로 재단도 작성 결과를 검토하였다. 단순모델의 해석요소수와 추출된 불연속 절점 수에 따른 보간 곡선 비교결과는 요소수가 큰 경우 추출된 절점의 수가 적은 것이 효과적이며, 최소자승 보간이 다른 방법보다 더 부드러운 재단 경계선을 제공한다.

• 한국정밀공학회지
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• 제13권2호
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• pp.133-145
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• 1996

This paper presents an indirect cutting force measuring system, which uses the current signals from the AC servo drive units of the horizontal machining center, with its applications to the adaptive regulation of the cutting forces in various milling processes and to the on-line monitoring of tool breakage. A typical model for the feed-drive control system of a horizontal machining center is developed to analyze cutting force measurement from the drive motor. The pulsating milling forces can be measured indirectly within the bandwidth of the current feedback control loop of the feed-drive system. It is shown that the indirectly measured cutting force signals can be used in the adaptive controller for cutting force regulation. The whole scheme has been embedded in the commercial machining center and a series of cutting experiments on the face cutting processes are performed. The adaptive controller reveals reliable cutting force regulating capability against the various cutting conditions. It is also shown that the tool breakage in milling can be detected within one spindle revolution by adaptively filtering the current signals. The effect of the cutter run-out has been considered for the reliable on-line detection of tool breakage.

• 한국정밀공학회지
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• 제15권4호
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• pp.105-110
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• 1998

In this study, statistical and neural network methods were used to recognize the cutting tool states. This system employed the tool dynamometer and cutting force signals which are processed from the tool dynamometer sensor using linear discriminent function. To learn the necessary input/output mapping for turning operation diagnosis, the weights and thresholds of the neural network were adjusted according to the error back propagation method during off-line training. The cutting conditions, cutting force ratios and statistical values(standard deviation, coefficient of variation) attained from the cutting force signals were used as the inputs to the neural network. Through the suggested neural network a cutting tool states may be successfully diagnosed.

• 산업기술연구
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• 제15권
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• pp.23-32
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• 1995

The methodology of automatic generation of tool path for rough cutting of a sculptured surface is proposed with the improved contouring method, unequal level line machining. Considering the surface shape and the diameter of the endmill, the distance between level lines is obtained. To improve MMR, initial rough cutting is processed with the large diameter endmill and the remained material is removed by the relatively small diameter endmill. Tool path is generated from the offset curve of respective level line and the interferences between the tool and workpiece are automatically avoided. After generating NC part program, the sculptured surface is machined at the vertical machining center. From the experimental results, total cutting length and machining time are reduced more effectively than conventional contouring methods.

• 한국정밀공학회지
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• 제20권4호
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• pp.214-222
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• 2003

Studies on the optimization of machining process can be divided into two different approaches: off-line feedrate scheduling and adaptive control. Each approach possesses its respective strong and weak points compared to each other. That is, each system can be complementary to the other. In this regard, a combined system, which is a feedrate control system fur cutting force optimization, was proposed in this paper to make the best of each approach. Experimental results show that the proposed system could overcome the weak points of the off-line feedrate scheduling system and the adaptive control system. In addition, from the figure, it can be confirmed that the off-line feedrate scheduling technique can improve the machining quality and can fulfill its function in the machine tool which has a adaptive controller.

• 반도체디스플레이기술학회지
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• 제19권4호
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• pp.51-58
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• 2020

Many types of optical plastic films are essential in optoelectronics display unit fabrication and it is important to develop high precision laser cutting methods of optical films with extremely low level of film surface contamination by fume particles. This study investigates the effects of suction and blowing air motions with air flow misalignment in removing fume particles from laser cut line by employing random particle trajectory simulation and probabilistic particle generation model. The computational results show fume particle dispersion behaviors on optical film under suction and blowing air flow conditions. It is found that suction air flow motion is more advantageous to blowing air motion in reducing film surface contamination outside designated target margin from laser cut line. While air flow misalignment adversely affects particle dispersion in blowing air flows, its effects become much more complicated in suction air flows by showing different particle dispersion patterns around laser cut line. It is required to have more careful air flow alignment in fume particle removal under suction air flow conditions.