• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.623-627
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• 1995

This paper deals with the process which automatically straightens the shaft whose straightness is over the tolerance. The developed straightening process is composed of the measuring module and the control module. In the measuring module, the deflection of each measuring point is automatically measured, and the press point and the reference press stroke is determined. In the control module, the springback is predicted by the observer using the calculated reference press stroke and on-line-measured force and deflection. Through a series of experiments, the validity of the proposed process was verified.

• 한국기계가공학회지
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• 제9권4호
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• pp.38-43
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• 2010

By generating 2-directional vibration in a xy plane of workpiece table, a newly developed micro drilling using 2-directional vibration was carried out. The vibration was produced by applying sinusoidal voltages to the orthogonally arranged piezoelectric materials built in the workpiece excitation table. Through the micro-drilling experiments using poly-carbonate and brass material, it was found that micro drilling using 2-directional vibration in a workpiece table could be an efficient method to enhance the form accuracy of machined workpiece by suppressing burr formation at both entry and exit region. A higher form accuracy could be obtained by increasing stiffness of feeding mechanism, decrease of geometric tolerance of combining jig, and development of high performance excitation table which generates amplified vibration at higher frequency.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.367-372
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• 2001

Feature restoration is that restore feature to 3D solid model using the feature information in STEP AP224. Feature is very important in CAPP, but feature information is defined very complicated in STEP AP224. This paper recommends the algorithm of extraction the feature information in physical STEP AP224file. This program import STEP AP224 file, parse the geometric and topological information, the tolerance data, and feature information line-by-line. After importation and parsing, store data into database. Feature restoration module analyze database including feature information, extract feature information, e.g. feature type, feature's parameter, etc., analyze the relationship and then restore feature to 3D solid model.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 추계학술대회 논문집
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• pp.34-38
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• 1992

Geometry based CAD/CAM system is hard to achieve "net shape machining" For a net shape machining, the machining errors should be compensated by off-line CAD/CAM system followed by on-line control system. In this paper, we investigate an off-line compensation scheme for the machining errors due to tool deflection in contouring operation. The significance of the deflection errors is first shown, and a compensation is sought via modifying the nominal tool path. In modification, tool deflection amount is iteratively compensated until the deflection amount is iteratively compensated until the deflected path results in the desired contour within a tolerance. The path modification algorithm has been tested via computer simulation. The developed algorithm can be used as a postprocessor for the current CAD/CAM system based on geometric modeling as a means for enhancing the machining accuracy.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2002년도 금형가공 심포지엄
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• pp.3-10
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• 2002

In this study on machine measuring system based on solid feature was developed. This system was applied with injection mold using 3 dimensional solid modeler for verification. Developed program include pre-processor, main processor, and post processor. In pre-processor there are functions which check intersection, simulate motion of probe and calculate measuring time. Main processor generates measuring path and output NC code in Unigraphics. In post-processor functions that include evaluation of undercut or overcut and display of measuring procedure are offered. In addition analysis module for quality control of measured data on manufactured product was developed with geometric and dimensional tolerance concept. As the result developed program could get stability of system, precision of product, rapidity and cost down of manufacturing process compared with before measuring process.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제17권3호
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• pp.171-179
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• 2013

In this paper we present a method of circular arc approximation by quartic B$\acute{e}$zier curve. Our quartic approximation method has a smaller error than previous quartic approximation methods due to the alternation of the error function of our quartic approximation. Our method yields a closed form of error so that subdivision algorithm is available, and curvature-continuous quartic spline under the subdivision of circular arc with equal-length until error is less than tolerance. We illustrate our method by some numerical examples.

• 한국컴퓨터정보학회논문지
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• 제4권4호
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• pp.25-33
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• 1999

서로 다른 기하학적 모델링 시스템을 사용하는 곡선 및 곡면의 자료 교환에서, 주어진 허용 오차 내에서 시스템이 지원하는 차수로 근사하는 차수감소를 종종 필요로 한다 본 논문에서는 기하학적 표현이 서로 다른 시스템간의 곡선 및 곡면의 교환에서 $\'{e}$의 차수감소에 의한 근사 변환 문제를 다룬다. 여러 가지 n차 $\'{e}$ 곡선을 n-1차 $\'{e}$ 곡선으로 감소하는 차수감소 방법들을 구현하고 각 방법들의 근사 변환한 실험적인 결과를 제공한다.

• 대한산업공학회지
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• 제19권4호
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• pp.49-70
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• 1993

The purpose of this study was to develop a semigenerative process planning system for the turning processes required for rotational parts. The system developed in this study showed three major roles for a given part : selection of appropriate turning processes, scheduling of selected processes, and selection of appropriate tools to be used for selected processes. Four information files and six modules were developed to produce a process plan. When geometric features, dimension, tolerance, material types, and surface finish data are inputted to the system, optimal processes, processing sequences, selected tools, and machining costs are to be produced as a process plan.

• Journal of Advanced Marine Engineering and Technology
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• 제19권1호
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• pp.54-59
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• 1995

In this paper, we propose unique CAM system for personal computer that can define the geometric shape in an ease manner and to machine the sculptured surfaces of a mold cavity. In this CAM system, if a user inputs simple initial information such as the control points for a shape definition and a radius of tool etc., all of the procedures for machining will be processed automatically by the CAM system as well as NC commands and simulations. In addition to this, the environment of the CAM system is composed of "C" language for an easy extention of aditional modules. Also, the CAM system with the following characteristics was developed. 1. The optimum tool path satisfying given tolerance limits reduces the time for the high precision machining of sculptured surface in a mold cavity. 2. The generated NC commands can be transmitted to NC directly by the CAM system through RS-232C from PC.C from PC.

• 한국콘텐츠학회논문지
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• 제9권11호
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• pp.254-261
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• 2009

본 연구는 진단용 CT 장치를 이용한 CT-모의치료기의 테이블 및 레이저 정렬 시스템과 횡단면 영상의 중심간 정렬을 개선하기 위한 효율적인 방법을 제안하고자 하였다. 본원에서 제작한 팬텀을 이용하여 AAPM TG66에서 제시하는 일일 정도관리를 시행하고 기하학적 삼각함수를 이용하여 레이저 정렬 시스템을 교정하였으며 교정 전, 후를 비교함으로서 교정방법에 대한 효율성을 검토하였다. 교정 전 영상의 중심간 오차는 3.82mm, 테이블 종축은 $0.436^{\circ}$ 틀어져 진행하였다. 기하학적 삼각함수를 이용한 레이저 정렬 시스템의 교정 후 0.7mm의 중심간 오차가 발생하여 ${\pm}2mm$의 허용오차 범위를 만족하였다. 설치 가동 중인 진단용 CT 장치를 방사선치료 전용 CT-모의치료기로 활용하는 경우 기하학적 정확도를 만족시키기 위한 테이블 교정은 기술적인 한계 뿐 만 아니라 시간 및 경제적 손실에 비하여 매우 비효율적이다. 그러나 레이저 정렬 시스템을 이용한 교정 방법은 경제적이고 비교적 간단하면서도 만족스러운 기하학적 정확도를 얻을 수 있어 임상에서 적용할 수 있는 효율적인 방법이라 사료된다.