• Transactions of Materials Processing
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• v.9 no.6
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• pp.567-573
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• 2000

An analysis system for evaluating the design of dieface of stamping press dies is developed. The die design analysis system interfaced with CATIA via universal or NASTRAN data format provides the design information such as binder-wrap, punch contact status, section length change ratio, wrinkle symptom etc., which are crucial in predicting the defects of initial shape of the sheet in the dieface design stage. The graphic post-processor of developed system which displays 3-dimensional shapes of tool and die and analysis results, helps the interpretation of design evaluation. The dieface design analysis system was tested in draw dies of front floor panel and quarter panel of auto-body in order to verify the usefulness and validity of the system The examples show that the developed system would be a good tool in evaluating dieface designs.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.34 no.2
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• pp.103-111
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• 2011

The reduction of setup time is very important in a lot production system. A punch press is a typical system of lot production. This paper describes a case study to reduce setup time of a punch press manufacturing system. Especially, this case study reduced the time of die exchange in the case that the standardization of die height is impossible realistically because of diversity on die height and heavy expenses. This study adopts a supplementary die and supplementary blocks to make the use of auto-clamping device possible. The paper also gives a sequencing algorithm to reduce the number of exchange of the supplementary die.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.12
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• pp.856-865
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• 2015

In a high-speed press, numerous moving links are interconnected and each link executes a constrained motion at high speed. As a consequence, high-level dynamic unbalance force and unbalance moment are transmitted to the main frame of the press, which results in unwanted vibration and significantly degrades manufacturing accuracy. Dynamic unbalance force and unbalance moment inevitably transmits high-level vibrational force to the foundation on which the press is installed. Minimizing the vibrational force transmitted to the foundation is critical for the protection of both the operators and the surrounding structures. The whole task should be carried out in two steps. The first step is to reduce dynamic unbalance based upon kinematic and dynamic analyses. The second step is to design and build an optimal vibration isolation system minimizing the vibrational force transmitted to the foundation. Firstly, the dynamic design method is presented to reduce dynamic unbalance force and moment. For this a 3D CAD software was utilized and a computer program was written to compute dynamic unbalance force and moment. Secondly, the design method for vibration isolation system is presented. The method for designing coil springs and viscous dampers are explained in detail.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.8
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• pp.42-47
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• 2010

In this paper, the characteristics of contact surface damage due to fretting in a press-fitted shaft below the fretting fatigue limit are proposed by experimental methods. A series of fatigue tests and interrupted fatigue tests of small scale press-fitted specimen were carried out by using rotating bending fatigue test machine. Macroscopic and microscopic characteristics were examined using scanning electron microscope (SEM), optical microscope or profilometer. It is found that fretting fatigue cracks were initiated even under the fretting fatigue limit on the press-fitted shafts by fretting damage. The fatigue cracks of press-fitted shafts were initiated from the edge of contact surface and propagated inward in a semi-elliptical shape. Furthermore, the fretting wear rates at the contact edge are increased rapidly at the initial stage of total fatigue life. After steep increasing, the increase of wear rate is nearly constant under the load condition below the fretting fatigue limit. It is thus suggested that the fretting wear must be considered on the fatigue life evaluation because the fatigue crack nucleation and propagation process is strongly related to the evolution of surface profile by fretting wear in the press-fitted structures.

• Korean journal of communication and information
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• v.40
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• pp.114-149
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• 2007

This study aims to examine how practices in beats have changed before and after the opening of press rooms and the operation of the briefing system. This research conducted in-depth interviews with 19 beat reporters and government officials. In conclusion, results showed that the Participation Government's press policy had a significant influence on practices in the press room. The opening of the press room and the operation of the briefing system contributed to the improvement of several bad practices in beats. However, some negative aspects of the briefing system were found in the research. Beat reporters' interviews were limited, thus threatening citizens' rights to know.

• Proceedings of the Korea Database Society Conference
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• 1997.10a
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• pp.129-136
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• 1997

The Multimedia Press System is an integrated tool for electronic archiving and evaluating articles and documents from all types of media. It may be used by the following departments of a company, a government agency or other organisations in their work with the media and publications: 1. press and/or public relations 2. information and/or documentation 3. internal relations 4. investor relations 5. marketing and advertising 6. economics. It may also be used in 7. independent agencies for public relations and advertising and in 8. media-archives of publishing houses and broadcasting stations.(omitted)

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.418-421
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• 2001

Press brake is used as bending and forming sheet metal in vehicle and many kind of industry. This paper deals with development of NC press brake based on high precision positioning device and software, which can be operated on personal computer. In this system, positioning device is used for controlling bending angle and operated by the developed software, which is database from material property, width and thickness of material. This study will make distribution in development of computer aided press brake.

• Korean Journal of Computational Design and Engineering
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• v.14 no.5
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• pp.314-322
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• 2009

In these days, automotive companies are trying to develop new manufacturing technologies and paradigms for rapid product development and production. The press die development process account for 40% of entire vehicle development process, and tryout process usually takes 3 to 4 months, and it is the biggest time portion out of dies manufacturing. Therefore, the effective tryout management system is essential to reduce time and cost of automotive press die production. This paper suggests improved process and practical application of tryout management using ubiquitous technology, and shows the results such as shorten time, improved quality and supporting of lifecycle engineering of press die.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.252-252
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• 2000

The Resistance Spot Welding (RSW) has been considered as an inherently safe and reliable method far joining metals, and has been widely employed, especially in automobile body assembly shops, as a manufacturing process. In recent years, the requirement for more sophisticated quality control procedures has considerably grown in the mass production industries. The object of the application of servo control to spot welding gun is the improvement of quality control in the spot welding, one of conventional industrial areas. The important factors affecting welding qualities (shear strength, nuggest size, indentation depth) are welding current, welding time, and gun press force. Welding current and welding time are controlled by welding timer. But, the conventional welding guns using compressed air are out of control in changing gun press forces in welding process. In this paper, a servo gun welding system having a AC servo motor and a PC control system is presented. The main object of this paper is to estimate the influence of gun press force changes in the welding process (press time -> welding time -> hold time) to welding qualities, and to evaluate welding qualities in real time, by recognizing the patterns of gun press forces changed in the welding process and comparing with the standard patterns.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1501-1504
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• 2008

By applying sonic wave vibration technology in weight exercise equipment, we introduced an completely new concept of device into the fitness and medical industry creating a new trend. Sonic wave leg press exercise system which got over the limit of technology will be easily accessible not only by professional athletes but also by ordinary users and even minority groups such as disabled, elderly, children.