• 동력기계공학회지
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• 제9권3호
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• pp.66-70
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• 2005

Structural components for aerospace, electronics and automobile industry are the main applications for magnesium alloys due to their lightweight and high specific strength. The adoption of magnesium alloys in sheet forming processes is still limited, due to their low formability at room temperature caused by the hexagonal crystal structure. In this paper, the authors aim to improve the formability of AZ31 magnesium alloy. For this, experiment and finite element analysis on used warm deep drawing process with a local heating and cooling technique were done. Both die and blank holder were heated at various warm temperature while the punch was kept at room temperature by cooling water.

• International Journal of Advanced Culture Technology
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• 제3권1호
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• pp.68-77
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• 2015

This study was the use of the finite element method in the deep drawing process of a rectangular shell cup. The aim was to analyse the equivalent strain in the workpiece and to find out what happened to the disc blank sheet before the forming by stamping. The rectangular shell cup was $24{\times}30{\times}20$ mm. and made of 2mm.thick SUS 403 and SUS 304 stainless steel. There were 3 types of blank sheets: 1) square sheet 2) 45 degree angled edge cutting sheet 3) circular sheet. It was found out that the drawing up with the use of 3 types of blank sheet made of SUS 304 stainless steel had no risk in the workpiece. For the stamping of the rectangular shell that used a square sheet made of SUS 403 stainless steel, it was found out that there was no risk in the work piece, but with the use of 45 degree angled edge cutting sheet or round sheet, the work piece had a risk to be damaged.

• 대한기계학회논문집A
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• 제20권7호
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• pp.2246-2256
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• 1996

To investigate the effect of material and precess variables on stamping formability of sheet materials, simulations for the cup drawing and the Yoshida buckling test were carried out using ABAQUS, commercial nonlinear finite element analysis code. The various factor effects on stamping formability of sheet materials were analyzed by the designed process according to Taguch's orthogonal array experiment. Cup drawing simulation showed that local neckling was very sensitive to plastic anisotropy parameter of sheet material and friction coefficient between sheet and tool interface. Simulations for the Yoshida buckling test have clarified that buckling behaviour of sheet material was mostly susceptible to yield stress and sheet thickness mostly. However, plastic anisotropy parameter and strain hardening coefficient affect moderately buckling behaviour of steel sheets after the buckling initiation.

• 플랜트 저널
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• 제17권3호
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• pp.37-41
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• 2021

P&ID(Piping and Instrument Diagram)는 플랜트의 장치 및 계장 정보를 집약적으로 담고 있는, 엔지니어링 핵심도면이다. 한 장의 P&ID에는 심볼로 표현된 수백 여개의 정보들이 존재하며, 이에 대한 디지털 전산화 작업이 수작업으로 진행되고 있어 많은 인력과 시간이 소요된다. 기존 연구들은 CNN 모델을 이용하여 도면 객체 검출에 성공하였으나, 도면 한 장당 약 30분, 인식률은 90% 정도로 현장에서 구현하기에는 부족한 성능이다. 따라서 본 연구에서는 영역 검출과 객체 인식을 동시에 처리하는 1-stage 객체 검출 알고리즘을 제안하였다. 이미지 레이블링 오픈소스 툴을 이용하여 학습 데이터를 구축하고 딥러닝 모델 학습을 통해 도면 내 심볼 이미지 인식 방법을 제안한다.

• 대한기계학회논문집A
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• 제37권7호
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• pp.865-873
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• 2013

CNG 압력용기의 제조를 위하여 고성능 수평식 프레스를 이용한 딥드로잉과 아이어닝의 연속공정(D.D.I. 공정)이 도입되었다. 그러나, 몇몇 D.D.I. 공정 변수들은 현장 경험에 의존하여 결정되는 문제점이 있으며, 다이의 짧은 수명 역시 고성능, 저비용의 압력용기 제조를 위하여 필수적으로 개선되어야 한다. 본 연구에서는, 공정의 신뢰성 확보 및 다이 수명 향상을 위하여 기존 관련 연구 및 현장 경험을 바탕으로 드로잉비, 다이 간의 간격, 드로잉 다이의 라운딩 반경, 아이어닝 다이의 각도를 공정변수로 결정하였다. FEA 를 이용하여 각 성형 단계에서 찢어짐과 주름이 발생하지 않는 한계 드로잉비를 결정하였고, 다이 간의 간격, 드로잉 다이의 라운딩 반경, 아이어닝 다이의 각도에 대하여 실험계획법을 이용하여 최적 공정설계를 수행하였으며, 기존 공정에 의한 결과와 비교하여 효율성을 검증하였다.

• 소성∙가공
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• 제7권5호
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• pp.445-449
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• 1998

In order to obtain optimum process variables during the drawing of stainless steel sheets rectangular cup drawing tests were carried out with several technically available stainless steel sheets. As parameters on testing materials for die and punches lubrication and blank holding forces were selected. Testing parameters played an important role if the deformed material was thin. Effect of material properties on the deformation behaviors was also discussed by using testing parameters selected in this experiment. From the test results we suggest the appropriate conditions to be applicable to the actual manufacturing processes

• 소성∙가공
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• 제17권7호
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• pp.473-480
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• 2008

Sheet metal forming of Mg alloy is usually performed at elevated temperature because of the low formability at room temperature. Therefore, strain rates affected with the forming temperature and speed must be considered as important factor about formability. Effects of process parameters such as various temperatures and forming speeds were investigated in circular cup deep drawing. From the experimental results, it is known that LDR (Limit Drawing Ratio) increase as the strain rate increase. On the contrary, the FLD (Forming Limit Diagram) shows lower value as faster strain rate. Therefore, anisotropy values are investigated according to the temperature and strain rates at each forming temperature. R-values also represent higher value as faster strain rate. It is known that the formability can be different with the deformation mode on warm forming of AZ31 alloy sheet.

• 한국정밀공학회지
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• 제17권4호
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• pp.38-47
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• 2000

Recently, finite element method has been used as an effective tool in the design process of sheet metal forming. In the present study, an implicit method and an explicit method have been developed for 2D analysis and 3D analysis, respectively, and applied to several processes including plane strain draw bending and TWB sqaure cup drawing. Also, commercial codes are used for geometrically complex problems, such as tube hydroforming, "L" cup deep drawing and side frame forming. In this paper, basic formulations used in the methods are introduced and results obtained from the applications are discussed.discussed.

• 대한금속재료학회지
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• 제50권1호
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• pp.8-12
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• 2012

This study aims to analyze the formability property of surface texturing processed automotive steel sheet for improving the sheet forming property. In the paper, the effect of cavities fabricated using the laser surface texturing technique on automotive high strength steel sheets was studied. The frictional behavior of the sheet drawing is a function of interface parameters such as sheet surface roughness, holding force, contact pressure, etc. For these reasons, automotive steel researchers want to optimize the surface topography of automotive steel sheets in order to enhance the formability. Therefore, this study presents the behavior of deformation of a laser surface texturing steel sheet by considering the frictional operation during the deep drawing process.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1998년도 춘계학술대회논문집
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• pp.151-154
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• 1998

Stainless steel sheets are widely used to produce electrical appliances. But there are various problems occured in forming stainless steel sheets such as scratch, local fracture, earing. So the productivity of electrical appliances made of stainless steel sheets is decreased. And it is very important to improve the formability of stainless steel sheets. In this study, rectangular cup drawing tests have been carried out to obtain optimum process parameters for improving the formablity of stainless steel sheets. In the tests, selected process parameters are materials of dies and punches, lubricating conditions, and blank holding force. From the test results, we suggest the appropriate conditions to be applicable to the actual manufacturing processes.