• 산업경영시스템학회지
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• 제20권41호
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• pp.197-201
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• 1997

Presses are very used in industrial and commercial companies and are often the source of serious accidents occurring during operation. Most of accidents are due to inadequate design of the press machine. This paper presented an experiment which examined eye movement characteristics of the operators in the press operation. Continuous recordings of eye movements were made on five subjects in press operation. It was observed that the subjects stared longer at the die and did not stare at the switch. The eyemovemen patterns per cycle of the subjects were mostly identified as material container $\rightarrow$ die pattern type. The results could be used as basic data to establish a design guideline when manufacturer made the press machine.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.169-173
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• 2008

This study is concerned with adopting the hydroforming method in the front axle of the commercial vehicle. Generally the front axle of the commercial vehicle is made bγ the several operations of press forging. This product supports the big weight of the vehicle and load. The weight of the press forging parts is also so more than it of the press parts of the passenger car. So, we have studied the hydroforming method to lessen the weight of the front axle of the commercial vehicle. To apply the hydroforming method in the commercial vehicle, we had to use the operation of reducing the diameter of the used tube prior to the hydorforming operation.

• International Journal of Precision Engineering and Manufacturing
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• 제2권3호
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• pp.69-78
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• 2001

This paper presents a process and operation planning system and an NC code post-processor for effective machining of press dies for production of cars. Based on the machining feature, major parts of press dies are categorized into 15 groups and a standard process plan is defined for each group. The standard process plan consists of a series of processes where a process is defined as a group of operations that can be done with one setup. Details such as cutting tools, cutting conditions, and tool paths are decided at the operation planning stage. At the final stage of process and operation planning, the NC code post-processor adjusts feedrates along the tool path to reduce machining time while maintaining the quality. The adjustment rule is selected based on the machining load estimated by virtual machining.

• 한국정밀공학회지
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• 제18권1호
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• pp.63-73
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• 2001

This paper presents a process and operation planning system with an NC code post-processor for effective machining of press dies for production of cars. Based on the machining features, major parts of press dies are categorized into 15 groups and a standard process plan is defined for each group. The standard process plan consists of a series of processes where a process is defined as a group of operations that can be done with one setup. Details such as cutting tools, cutting conditions, and tool paths are decided at the operation planning stage. At the final stage of process and operation planning, the NC code post-processor we developed adjusts feedrates along the tool path to reduce machining time. The adjustment rule is selected based on the metal removal rate estimated by virtually machining with virtual cutting tool.

• 대한안전경영과학회지
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• 제1권1호
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• pp.55-60
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• 1999

Presses are very widely used in industrial and commercial companies and are often the source of serious accidents occurring during operation. In Korea, the press holds the first place in the industrial hazard machines for frequency of accidents. Most of the press accidents are due to the human error. Continuous recordings of eye and hand movements that included operating errors of five experienced subjects were made during the press operation. The results showed that significant differences were observed on eye fixation time, hand fixation time, and lead departure time between the operations that has errors and no errors. The result could be used as basic data to establish a guideline for preventing the accidents.

• 소성∙가공
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• 제17권8호
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• pp.643-648
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• 2008

Ultra-thin sheet metal forming techniques are required in precision forming of miniaturized and integrated products. In order to manufacture a good quality and low cost ultra-thin sheet metal products, a highly precise high-speed press is needed. The precision of a press is related with its vibration characteristics during pressing operation. This study evaluated the vibration characteristics of a proposed press design using computer simulation. The analysis compares the static deformation characteristics of the slide and the slide motion for the metal forming of an ultra-thin sheet of thickness less than 0.1mm. Further, in order to minimize the vibrations during high speed pressing operation, revolution balances of the eccentric shaft and the balance weight device is also considered. Finally, modal analysis is used to characterize the natural frequency of vibration of the press.

• 한국안전학회지
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• 제11권1호
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• pp.129-132
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• 1996

This paper presents an experiment which examines eye movement characteristics of novice and experienced workers in the press operation. Significant difference between the novice and the experienced workers was observed in fixation time, eye movement patterns, and spatial distribution of fixations when the top die hits the bottom die. There were no significant difference between the novice and the experienced workers in eye movement time. The results could be used to set up a guide to train the novice workers and to determine how long the novice should be trained.

• 대한인간공학회지
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• 제16권1호
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• pp.63-71
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• 1997

This paper presented an experiment which examined eye and hand movement characteristics of novice and experienced workers in the press operation. Continuous recordings of eye and hand movements were made on five novice operators and five experienced operators in press operation. Significant difference between the novice and the experienced operators was observed in eye fixation time, eye movement patterns, hand dwell time, and eye-hand coordination. Also, differences were observed in spatial distribution of eye fixations during the die-closing portion of a stroke. There were no significant differences between the novice and the experiencedoperators in the eye and the hand movement time. The results could be used to establish a guide determining the method and training period to train the novice operators.

• 한국언론정보학보
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• 제40권
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• pp.114-149
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• 2007

본 연구의 목적은 참여 정부의 기자실 개방과 브리핑제 시행을 전후해 기자실의 관행이 어떻게 바뀌었는지 알아보는 데 있다. 취재 관행의 변화를 분석하기 위해, 언론사 간 차별과 기자와 취재원의 유착, 출입기자 간 기사 담합, 촌지 수수와 향응, 방문취재 제한, 엠바고 처리 등의 6개 연구 문제를 설정하였다. 연구방법으로, 출입기자와 출입처의 공무원 등 19명과 심층 인터뷰를 하였다. 연구 결과, 노무현 정부가 펼친 기자실 개방과 브리핑제 시행이라는 언론정책은 기자실 관행에 상당한 영향을 미친 것으로 밝혀졌다. 즉, 기자실 개방과 브리핑제는 언론사 간 차별, 취재원 유착, 촌지 수수 등 기자실의 각종 폐단을 크게 개선시키는 등 긍정적으로 기여하고 있었다. 그러나 브리핑제 시행 이후 출입기자가 사무실 방문취재를 제한받으면서 결국 국민의 알 권리가 위협받는 등 부정적으로 기능하는 측면도 확인되었다.

• 한국염색가공학회지
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• 제17권5호
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• pp.53-60
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• 2005

Fusing press m/c is used for heating and pressing the specimens that are fed into between the two moving belts. Therefore the belt movement, belt temperature, and the pressure between belts must be kept constant. Especially, the belts should move in a limited operation range. When the belts run far out of the operation point, the machine has to be stopped, which results in a product defect because the fusing conditions, e.g., temperature and pressure, change during the transient process time period. It is important to avoid the belt stopping by maintaining the belt movement in a limited range. This study reports about the movement of the endless fusing belt in a long-span roller fusing m/c. The belt position changes as the 1st-order system does; if the roller axes are slanting each other with a certain angle, the belt running around the two rolls shows a dynamic behavior with the time that deviates fastly at the beginning from the initial condion and slows down. Then it reaches at a final position. The skewer the axes, the greater the position change. The inital change rate of the belt becomes large as the skewness of the axes between the two rollers increases.