• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.6
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• pp.669-675
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• 2011

A constant hanger is a device for supporting pipes in plants. It supplies a constant force to a supporting pipe even if the pipe moves because of thermal expansion. In this paper, we propose a method for designing the contour of a cam for a constant hanger. It has been shown that the contour of a cam must satisfy the geometrical relation of the cam, the force balance equation for the load tube, the relation between the side spring compression and the cam rotation angle, and the moment balance equation for the cam. A calculation procedure to solve these equations simultaneously is proposed, and a constant hanger is designed successfully.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.1
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• pp.73-79
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• 2016

Higher circuit breaker safety standards can be obtained by increasing the sustaining time of the latching section. This time increase is achieved through velocity reduction after contacting when the closing mechanism operates. The potential for the re-closing phenomenon to occur is also reduced by obtaining time to return open latch. In this study, the sustaining time for the latching section was increased through cam profile optimization based on the displacement response of the moving parts. In addition, the existing performance velocity was also satisfied. A multibody dynamics model of the circuit breaker was developed using ADAMS. To validate the model, simulation results were compared to experiment results. Then, cam profile optimization was carried out using an optimal design program PIAnO. Design variables selected included the radial direction of the cam. Design sensitivity analysis was carried out by design section as well. As a result of optimization, the sustaining time for the latching section was increased.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.7
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• pp.723-728
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• 2011

Since the performance of a vacuum circuit breaker (VCB) mainly depends on the spring operating mechanism, an analysis of the spring operating mechanism is required in order to improve the design of a VCB. In this study, the static stiffness of the spring was determined by using a material testing machine, and the test results were used to model the spring through computer simulation. The multi-body dynamic model of the spring was established by using the RecurDyn program. The dynamic model was verified by comparing the results of stem displacements and rotating angles of the brake shaft obtained from the simulation and from the experiments. After verification of the dynamic model of VCB, the cam profile of the VCB was optimized through multi-body dynamics simulation in order to improve the performance of the closing mechanism.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.2
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• pp.83-90
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• 2005

A mirror cam mechanism a kind of conjugate cam mechanism consists of two cams, two rollers, and two links. Since profiles of two mirror cam are identical, a simultaneous machining of two cams is achievable. Some machining errors on cam profiles do not result in the internal acting force, which often causes problems in high speed cam mechanism between two links. Also, since angular accelerations of two links are same, the internal acting force by the difference of the angular accelerations does not occur in the mechanism. Thus the mirror cam mechanism is very useful in high speed machinery. This paper studies a design method as well as a machining method, and develops an exclusive CAD/CAM software for mirror cam profiles. The developed CAD/CAM software is applied to a typical mirror cam mechanism and a mock-up equipment is built in order to test the machinism mirror cm. Experimental investigations show that the contact between cam surface and roller surface according to cam rotation agrees well with the simulation on the developed CAD/CAM software.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06c
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• pp.413-416
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• 2011

휴머노이드 로봇이 인간처럼 그림을 그리기 위해서는 순서를 가지는 드로잉 좌표 집합이 필요하다. 하지만 기존 영상 처리를 통한 윤곽선에서의 좌표 집합은 순서가 없고 로봇 암을 들어 올리는 좌표가 없다. 또한 불필요한 좌표가 다수 포함되어 있어서 효율적인 드로잉을 하기가 어려워 드로잉하는데 시간이 많이 걸린다. 따라서 본 논문에서는 3축으로 구성된 휴머노이드 로봇 암이 드로잉하기 위한 좌표 집합을 추출하는 알고리즘을 개발한다. 이를 구현하기 위해서는 로봇이 드로잉하기 위한 윤곽선 추출 알고리즘과 추출한 드로잉 좌표 집합에서 드로잉 순서와 로봇 암을 들어 올리는 점을 전체 좌표 리스트에 포함해야 한다. 제안하는 알고리즘이 추출하는 좌표 집합은 캠 영상으로부터 입력되는 컬러 이미지에서 이미지 프로세싱을 거친 윤곽선을 입력으로 하며, 추출한 좌표들의 순서와 로봇 암의 드로잉 시작점을 삽입함으로서 빠르고 효율적인 로봇 드로잉 좌표 집합 추출 알고리즘을 구현한다. 또한 제안하는 추출 알고리즘을 휴머노이드 로봇에 적용하여 실험하였으며, 좌표 추출 알고리즘의 정확성과 효율성을 비교하였다.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.4
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• pp.369-375
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• 2011

Design is important in the IT, digital appliance, and auto industries. Aesthetic and art images are being applied for better quality of the products. Most image patterns are complex and much lead-time is required to implement them to the product design process. A precise reverse engineering method generating 2.5D engraving models from 2D artistic images is proposed through the image processing, NURBS interpolation and 2.5D reconstruction methods. To generate 2.5D TechArt models from the art images, boundary points of the images are extracted by using the adaptive median filter and the novel MBF (modified boundary follower) algorithm. Accurate NURBS interpolation of the points generates TechArt CAD models. Performance of the developed system has been confirmed through the quick turnaround 2.5D engraving simulation linked with the commercial CAD/CAM system.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.3
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• pp.263-270
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• 2019

Current trends in restorative dentistry focus on improving the esthetics and keeping the sound dental tissues as long as possible. The aims of this case report were to describe the successful outcome of cubic-phase zirconia laminate veneers for a patient with isolated microdontia by using a digital workflow, and to describe their clinical implications. A 15-year-old female who had isolated microdontia in combination with spacing visited Ajou University Dental Hospital for esthetic treatment. In this case, 6 maxillary anterior teeth were restored with cubic-phase zirconia laminate veneers without tooth structure removal by using a digital impression, computer-aided design (CAD) software, and computer-aided manufacturing (CAM) procedures. At 6-month follow-up, no distinct mechanical and biological complications were detected and the prostheses exhibited satisfactory esthetics and functions. Due to its favorable tissue responses and enhanced translucency, cubic-phase zirconia can be a suitable strategy for a noninvasive esthetic approach.