• International Journal of CAD/CAM
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• 제3권1_2호
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• pp.85-95
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• 2003

During the design of dies and molds, the cavity of the object is obtained by subtracting it from a surrounding rectangular block. This box is subsequently split into two halves by the parting surface. Similar problems also occur in some RP processes such as LOM, SGC, SLS and 3DP where the machine produces a block inside which the prototype is buried. Determining the orientation of the object inside the box and the corresponding parting surface taking appropriate constraints into account have been addressed by several researchers. However, given the parting surface, the problem of splitting the box development of a software package called OptiLOM (now a module of an RP software Magics 8.0), the authors realized non-triviality of this problem since the loop can spread over as many as 5 faces of the box. In this paper, the authors have tried to bring out the importance of this problem and have presented their algorithm to solve it.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.697-704
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• 2000

This study presents methodology and tools for remote measurement of the orientation of the rock parting surfaces. Two close circuit video camera capture the pictures of a rock excavation surface while a laser beam scans the surface. Positions of the laser beams in the two digital images are recognized by image processing. Using the stereoscopic concept, three dimensional coordinations of the rock surface and the orientation of the rock parting planes are calculated. Point, cross and line type laser beams are tested for better image processing results and measurement accuracy of the coordinates. According to a simple accuracy test, cross beam show better results than the point beam. However, line beam show more promising results for the measurement of the rock parting surfaces.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.245-250
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• 1999

In order to design micro-fan appropriately, flow chacracteristics and mechanics should be carefully considered. The present work concerns with design procedure for a micro-fan using NACA(National Advisory Committee for Aeronautics) airfoil series. The generation of fan profiles is carried out automatically by defining related parameters, which is also converted to CAD/CAM data automatically. The optimal parting surface for the mold of micro-fan is also calculated by analyzing the geometric data numerically. As a consequence, the high capacity micro-fan can be developed successfully with a high-quality and an improved efficiency.

• 산업공학
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• 제13권4호
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• pp.591-598
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• 2000

In this paper, an efficient algorithm is proposed to find parting lines(PL) and generate parting surfaces(PS) for an injection mold design. We used a Face-Edge Graph which can be made by B-rep information of solid model. The graph is useful for finding the peripheral-loop edges for PL and the inner-loop edges for hole-patch. The PS can be generated automatically by selecting pre-defined direction lines. We can create a core and cavity molds by trimming the raw stock block with the PS and the upper/lower faces of a product model. We implemented proposed method with Unigraphics API functions and C language, and tesed on Unigraphics V15.

• 소성∙가공
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• 제20권1호
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• pp.73-78
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• 2011

The flashing reduces the part quality and the productivity of the molding process. We developed a contact pressure sensor to detect the flashing immediately. The performance of the sensor was analyzed in a simple 2D simulation. The sensor was applied to an automotive bumper mold with cavity pressure sensors. It showed sensitive output signal for the mold response by the cavity pressure change. It was confirmed that the flashing at the gate area occurred in the filling stage by the pressure increase due to growth of the melt flow length. The sensor output was correlated with the cavity pressure sensor output.

• 한국정밀공학회지
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• 제22권1호
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• pp.103-108
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• 2005

In this study, to develop a flash-less mold for forming of shoe-outsole, experiments and forming analysis were carried out. In order to reduce the extra-materials, offset method and mass distribution method are used in the preform design. The vertical mold structure pressing the preform was introduced to produce a flash-less shoe-sole. To measure the contact status of parting surface of mold, the pressure film has been used. The guide-gutter system and the continuous pressing mold have been developed for the discharge of extra-materials and re-pressing. By the investigation, flash of shoe-outsole was considerably reduced.

• 한국정밀공학회지
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• 제22권1호
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• pp.109-114
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• 2005

In this study, to develop a flash-less mold for forming of shoe-midsole, experiments and forming analysis were carried out. In order to reduce the extra-materials, the final preform has been modified by the experiment of pressure forming at the room temperature. To measure the contact status of parting surface of mold, the pressure film has been used. The midsole mold of the wedge structure type has been developed for the improvement of the contact status. The vertical pressing mold structure was introduced for the production of a flash-less midsole. By the investigation, flash of shoe-midsole was considerably reduced.

• 한국CDE학회논문집
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• 제5권2호
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• pp.196-205
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• 2000

This paper proposes a topology-based algorithm for recognizing the passage features using a concept of multi-face hole loop. The Multi-face hole loop is a concetpual hole loop that is formed over several connected faces. A passage feature is recognized in the proposed approach by two multi-face hole loops that constitute its enterance and exit. The algorithm proposed in this paper checks the connectivity of the two multi-face hole loops to recognize passage features. The total number of passage features in a part is calculated from Euler equation and is compared with the number of found passage features to decide when to terminate. To find all multi-face hole loops in a part, this paper proposes an algorithm for finding all combinations of connected faces. The edge convexity is used to judge the validity of multi-face hole loops. By using the algorithm proposed in this paper, the passage features could be recognized effectively. The approach proposed in this paper is illustrated with several example parts.

• 한국전기전자재료학회논문지
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• 제33권2호
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• pp.135-140
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• 2020

An experimental study was conducted using the tracking wheel test (IEC 62217) method for evaluating the performance of insulator materials, in particular ethylene propylene diene monomer (EPDM) and silicone rubber. In addition, we studied the tracking characteristics resulting from applying the same method for the shape of the insulator housing, that is, the performance of regular and alternating sheds. The evaluation parameters were leakage current, surface characteristics, SEM, EDX, hydrophobicity, and temperature distribution; likewise, we applied the commercial frequency dry (and wet) flashover voltage test. We found that the regular shed had a greater leakage current than the alternating shed and that the recovery of the hydrophobicity in terms of rest time was greater than that of the EPDM in terms of leakage current. All of the regular-shed insulators of silicone rubber had tracking traces and choking on the sheath parting line, while the alternating shed showed only choking at the interface but no tracking traces. Therefore, it can be concluded that the commercial frequency wet flashover voltage of the silicone rubber with regular shed before and after the tracking wheel test is higher than that of the alternating shed.

• 박물관보존과학
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• 제15권
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• pp.4-25
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• 2014

국립춘천박물관이 소장하고 있는 수다사지 청동금고는 1987년 강원도 평창군 진부면 수항리에서 발견되었다. 금고 표면에, 제작 당시의 주조 결함과 보수 흔적이 다수 발견되어 제작 기법을 유추하기에 용이한 중요 자료이다. 본 연구에서는 금고의 성분, 주형과 채플릿^{Chaplet, 형지(型持), 코어받침쇠}의 위치, 결함의 원인 등을 과학적으로 조사하여 주조 기법과 당대의 보수 방식을 추정해 보았다. 성분 분석 결과, 금고의 주성분은 구리 71.6wt%, 주석 18.2wt%, 납 7.2wt%로 3원계 청동합금이며 비소·안티몬이 각각 약 1wt%씩 검출되었다. 주조 시 주형을 고정하기 위하여 사용한 채플릿의 성분은 납 함량이 금고보다 더 높으며, 제작 후 구멍을 메우기 위해 사용된 땜납의 성분은 납 함량이 가장 높게 나타났다. 주조 분할선을 토대로 표면 상태를 관찰한 결과 사형주조 ^砂型鑄造로 제작되었을 가능성이 높았으며, 표면 관찰 및 방사선투과조사로 냉접^{Cold shut}이나 표면 주름^{Surface Folds}, 미스런^Misrun, 채플릿 주변의 기공^{Blowholes Adjacent to Chaplets} 등의 주조결함을 확인하고 발생 원인을 추정하였다. 보수된 부분은 제작 당시의 주조 결함인 구멍이 생긴 부위를 메우기 위하여 연납을 사용한 땜질보수 ^{Soldered-in Repair}를 하였다.