• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 춘계학술대회논문집
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• pp.55-58
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• 1997

In automotive industries, stamping of laser-welded blank gives many merits which brings about dimensional accuracy, strong body assembly and high productivity. However the welding of blanks with different thickness or/and different strength materials introduces many challenging formability problems for process development and tool design. In this paper, the deformation characteristics for deep drawing process of laser-welded blank with different thickness sheets are investigated by experiment and FEM simulation. And also the optimal location of weld line in laser-welded blank with different thickness sheets is calculated to compensate for the movement of weld line on deep drawing process. In addition, the effect of location of weld line is clarified using FEM simulation.

• 소성∙가공
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• 제24권6호
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• pp.400-404
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• 2015

For mass production of stamped parts, which require complicated in-press operations, it is always advisable to use a progressive die set. It is difficult to choose a progressive die set if the stamped parts need to be deep drawn and especially if they are unsymmetrical. Because unsymmetrical deep drawing parts are very sensitive to the effect of weight during moving to the next step, they are hard to exactly locate on the die face. An automotive seat side cushion panel is about 80mm high, unsymmetrical and its low edge needs hemming, so it is hard to produce even using a progressive die set. In the current paper a progressive stamping for seat side cushion panel was examined. Five strip bridges were considered to be strong enough to move to the next die as predicted by the CAE analysis.

• 한국기계가공학회지
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• 제3권4호
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• pp.43-49
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• 2004

The production parts have required multiple processes such as drawing, piercing, blanking and notching etc. are performed with a high production rates in progressive die. In order to prevent the defects of process result, the optimization of strip process layout design, die design, die making, and tryout etc. are needed. According to these factors of die development process, it has been required that the theory and practice of metal working process and its phenomena, die structure, machining conditions for die making, die materials, heat treatment of die components, processing know-how and so on. In this study, we designed and analyzed die components through the carrying out of upper relevant matters also simulated the strip process layout of multiple stage drawing by DEFORM. Especially the result of tryout and its analysis became to the feature of this study with a system of PDDC(Progressive Die design by computer).

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.754-758
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• 2000

Milli-structure components are classified as component group whose size is between macro and micro scale. that is, about less than 20mm and larger than 1mm. The forming of these components has a typical phenomenon of bulk deformation with thin sheets because of the forming size. In order to conventional metal forming, where numerical process simulation is already fully applied, the micro-forming process is characterized by some scale effects which have to be considered in an advanced process simulation. milli-structure rectangular cup drawing is analyzed and designed using the finite element method and experiment. The result of the finite element analysis is confirmed by a series of experiments.

• 대한기계학회논문집
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• 제9권5호
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• pp.677-682
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• 1985

극치해석적인 상계정리를 기초로 하여, 평면변형 인발에서 발생하는 내부결함(central bursting)을 예측하기 위해 중심에서 공동(voids)을 가진 금속에 대해 비례흐름(proportional flow)과 내부결 함의 흐름을 비교하여 해석하였다. 이 결함을 촉진시키는 공정조건에 대한 판정식(criterion)을 변형경화 금속에 대해 유도하였다. 공동을 가진 금속은 공동들을 축소시키기 위해 정상적인 재 료(sound material)의 흐름과 동일 방법으로 흐를 수 있으며, 경우에 따라서는 내부결함을 확장 하기 위해 흐를 수도 있다. 본 연구에서는 다이의 경사각, 단면감소율 및 마찰 등의 어떤 공정 변수 영역에서 중심축 상에 많은 공동을 가진 변형경화 금속에서도 내부결함이 발생할 수 있다는 것이다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.31-35
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• 2000

We investigate the groundwater distribution and chemical characteristics for 3 or 5 districts every year and make the hydrogeologic map on a scale of 1:50,000. We draw the hydrogeologic digital map based on "The Handbook for the Drawing and Management of Hydrogeologic Map" which was published by MOCT and KOWACO in 1998. But, the Stiff diagram and well's notation are difficult to be presented in the digital map using the commercial Arcview GIS tools. So we develop the script file with Avenue language to represent them in Arcview GIS tool. At first, we design the database for the chemical analysis result of groundwater and well identification, and make the program code with Avenue language to display them on the digital map. And next we test the usefulness of the program code. As a result, we find that the script file is very useful for drawing the symbols and diagrams in hydrogeologic digital map using ArcView GIS.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2002년도 춘계학술대회 논문집
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• pp.121-124
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• 2002

This paper resents a virtual forming system to simulate deep drawing process for stress-strain information by utilizing virtual system designed using Virtual Reality Modeling Language (VRML) and computer aided analysis (CAE) tool. The CAE tool to calculate stress, strain, and deformation is designed using Finite Element Method. Stress distributions and deformation profiles as well as the operation of forming machine can be simulated and visualized in the web. The developed system consists of three modules, input module, virtual forming machine module, and output module. The input nodule was designed using HTML and ASP. The input data for FEM calculation is directed to the forming machine module for calculation. The results from the forming machine module can be visualized through output module as well as the forming process simulation.

• 소성∙가공
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• 제5권4호
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• pp.281-287
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• 1996

Two kinds of blank shapes optimum and square are adopted to investigate formability. Optimum blank shape is determined to construct an L-shape cup with uniform height and without flange part. For this purpose rigid-plastic FEM analysis is applied with backward tracing technique. Maximum cup depth and strain distribution are measured experimentally for the products of the two kinds of blank shapes which are optimum and square. it is confirmed that deeper cup without severe thickness reduction can be obtained from the optimum shape.

• 소성∙가공
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• 제17권2호
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• pp.91-96
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• 2008

The governing parameters affecting the fatigue properties have been investigated experimentally in the high carbon steel wires with 0.94 wt.%C. In order to find the crucial factors, the advanced analysis techniques such as optical 3-D profiler, focused ion beam(FIB) and transmission electron microscope(TEM) were used. The two-type steel wires with different drawing strain were fabricated. The fatigue properties were measured by hunter rotating beam tester, specially designed for thin-sized steel wires. It was found that the fatigue properties of the steel wires with high drawing strain was higher than that with other wires because of low residual stress and high adhesion condition of brass coating layer.

• 한국표면공학회지
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• 제36권5호
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• pp.398-405
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• 2003

The stainless steel wire requires good corrosion resistance and mechanical properties, such as drawing ability, combined with a high resistance to corrosion. For increasing drawing ability of stainless steel, Ni coating methods have been used in this study. However, there is no information on the electrochemical corrosion behavior of drawed wires after Ni coating. To investigate corrosion resistance and mechanical property of drawed wire, the characteristics of Ni coated wires have been determined by tensile strength tester, hardness tester, field emission scanning microscope, energy dispersive x-ray analysis and potentiodynamic method in 0.1 M HCl. The drawed stainless steel wires showed the strain-induced martensitic structure, whereas non-drawed stainless steel wire showed annealing twin in the matrix of austenitic structure. The hardness and tensile strength of drawed stainless steel wire were higer than that of non-drawed stainless steel wire. Electrochemical measurements showed that, in the case of drawed stainless steel o ire after Ni coating, the corrosion resistance and pitting potential increased compared with non-coated and drawed stainless steel wire due to decrease in the surface roughness.