• 소성∙가공
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• 제8권1호
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• pp.38-46
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• 1999

This paper deals with the shape fixability of press formed parts through the use of a V-bending process and a U-bending one. The influence of material properties on the shape fixability in forming processes was investigated. A V-bending process had on optimum ben radius for each combination of parameters which caused maximum shape fixability. In the U-bending process the blank holder force could control the degree of shape fixability. A ha호 blank holding force resulted in a uniform strain distribution and increased shape fixability.

• 한국정밀공학회지
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• 제23권5호
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• pp.51-58
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• 2006

The necessities for heightening fuel efficiency as well as lightweight design, lead to an increase of the use of aluminum alloys in the automobile industry. Extruded aluminum profile channels are used widely for the design of frame parts as lightweight assemblies, especially if a high stiffness is needed. While many applications can be realized with forming of hollow square-sectioned extruded profiles such as a stretch bending and a hydro-forming, some applications demand the use of a press bending which can be hardly found in the previous study. In this study, by introducing the use of a press bending into car sub-frames, the demands for higher accuracy as well as higher flexible method than the conventional methods will be satisfied. With respect to the design of sub-frames, the process planning was performed from the shape of a sub-frame product. The designed processes were analyzed by the commercial FEM code, DEFORM-3D. Forming dies for the each process were designed and prototypes of sub-frames were manufactured by the verified farming process. In addition, some of the important features of design parameters in the press bending were reviewed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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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.

• 한국자동차공학회논문집
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• 제25권1호
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• pp.74-81
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• 2017

The door impact beam of the side-impacted vehicle plays a key role in securing occupant safety by preventing intrusion from the impacting vehicle. Despite the low production cost, the press door impact beam has been adopted sparingly because of the strength inferiority. In this study, the design technologies of the press beam aimed at improving bending strength were investigated. First, the effect of the section shape and size was examined. Next, thickness and material strength were increased. Also, the TRB beam application was simulated by varying combined thickness. Some TRB beams with reduced weight exhibited bending strength over the strength of the pipe beam. Then, the beam with a closed center section also showed remarkably enhanced maximum bending strength.

• 자동차안전학회지
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• 제11권1호
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• pp.40-47
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• 2019

First, three point bending analysis for the inclined press door impact beam was carried out to investigate inclination angle effect on the maximum strength with varying support distance. Next, for the system model with spring elements representing body stiffness at door mounting area, the bending structural behavior of impact beam mounted on vehicle was estimated. The mounting distance and inclination angle were changed and the beam bending buckling strength was presumed at the head displacement below which spring stiffness change has little effect on the load. Finally strength ratio to predict the bending buckling strength of impact beam mounted on vehicle from three point bending maximum strength of fixed support distance was suggested.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.811-812
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• 2010

• 소성∙가공
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• 제18권1호
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• pp.13-19
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• 2009

In the recent years, the production of light-weight products has become important because of increasing demands for the energy savings through weight reduction. Therefore the advanced manufacturing technology with Al alloy is continuously required in many industrial fields. Bending characteristics of Al rectangular tube with hollow and solid section has been analyzed by FE analysis in press bending with wing-die. Bending stress is affected by punch stroke and rotation of wing-die. There were different sectional sagging characteristics between the solid rectangle section and the hollow rectangle section.

• 대한기계학회논문집A
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• 제33권11호
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• pp.1267-1273
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• 2009

Hot press forming can produce high-strength components by rapidly cooling between closed punch and die after hot forming using quenchable boron steel austenized in a furnace. In the hot press forming process, the cooling rate is influenced by the size, position and arrangement of the cooling channel and the file condition of cooling water in the die. Also, mechanical properties of the final components and operation time are related to cooling rate. Therefore, the design of optimized cooling channel is one of the most important works. In this paper, the effect of position and size of the cooling channel on the cooling rate was investigated by using design of experiment and FE analysis in hot press bending process. Therefore the optimum cooling channel ratio was presented in the HPB.

• 소성∙가공
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• 제20권2호
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• pp.110-117
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• 2011

The purpose of this work is to develop of a press forming process for mobile phone battery cover as an alternative to the current manufacturing process by laser welding. This press forming process consists of a combination of bending, side pressing and side bending operations. The dimensional error for each process was investigated by finite element(FE) analysis and the Taguchi optimization method. The spreading of the cover width in the side pressing process was adjusted by modifying the blank shape with a notch. The over-bending method was adopted to compensate the spring-back which occurs after bending. Forming experiments were performed to verify the reliability of the developed press forming process. In addition, the strength of the product was evaluated to verify the suitability of the battery cover manufactured with this new press forming process. The results of the forming experiments indicate that the dimensional accuracy of the battery cover is within the required tolerance. The strength of the battery cover was evaluated to 547N which is larger than required strength of 400N.

• 대한기계학회논문집A
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• 제38권3호
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• pp.251-258
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• 2014

선루프 트랙은 알루미늄을 압출하고 프레스성형하여 생산한다. 프레스성형 중 날카롭게 굽혀진 좌면의 가장자리를 따라 균열이 발생하였다. 좌면의 가장자리를 절단하여 펀치와 다이 모서리의 최종위치를 측정하고 균열발생과의 관계를 조사하였다. 그리고, 이 최종위치까지 굽힘을 유한요소 시뮬레이션하여 임계변형률을 구하였다. 한편, 소재의 방향, 경도, 굽힘 가장자리 길이, 굽힘반경의 여러 가지 다른 조합에 대하여 3점굽힘시험을 수행하였다. 그리고, 3점굽힘시험에 대한 유한요소 시뮬레이션을 수행하여 임계변형률을 구하여 비교하였다.