• Title/Summary/Keyword: Blank holder gap

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Analysis on the Bending Deflection of the Blank Holder in Automotive Body Panel Draw Die (차체용 드로우 다이의 블랭크 홀더 굽힘 변형 해석)

  • 인정제;신용승;김헌영;김재우;송명환;박진수
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.10a
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    • pp.249-254
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    • 2000
  • The contact forces between die components for the drawing of large size automotive panels introduce elastic deflections of the die components. Due to the deflections, the gap between blank holder and die varies locally resulting in nonuniform material flow. Such a nonuniform die gap usually requires correcting operation, so called die spotting, which is time consuming trial and error process. To reduce the die spotting time, the optimization of the blank holder bending deflection is needed. In this paper, we implemented an analysis procedure to predict the blank holder deflection. The analysis procedure and design of experiments techniques are applied to the optimization of balance block heights. The optimization results can be used as guidelines in actual die spotting process.

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Analysis on the Bending Deflection of the Blank Holder in Automotive Body Panel Draw Die (차체용 드로우 다이의 블랭크 홀더 굽힘 변형 해석)

  • 인정제;신용승;김헌영
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.10 no.3
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    • pp.68-74
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    • 2001
  • In the drawing of large size automotive panels, elastic deflection of die components is induced by the contact force between them. The deflection is nonuniform and locally distributed, and results in nonuniform material flow. In order to arrange such a nonuniform die gap, a correcting operation, so called die spotting, is inevitable, which requires trial and error works and consuming time. A prediction of the bending deflection prior to a try-out must be useful to reduce the die spotting time. In this study, drawing process of a front fender is simulated first. and the deflection of the blank holder is calculated from the contact force imposing on th blank holder. The balance block heights ensuring a uniform deflection are optimized by the analysis and design of experiments.

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Experimental Study on the Size Effect and Formability of Sheet Materials in Microscale Deep Drawing Process (마이크로 딥 드로잉 공정에서 박판소재의 크기효과 및 성형성에 관한 실험적 연구)

  • Nam, Jung Soo;Lee, Sang Won;Kim, Hong Seok
    • Journal of the Korean Society for Precision Engineering
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    • v.32 no.9
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    • pp.793-798
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    • 2015
  • This study investigates the effects of the size of copper sheets on the plastic deformation behavior in a microscale deep drawing process. Tensile tests are conducted on the copper sheets to study the flow stress of the materials with different grain sizes before carrying out the microscale deep drawing experiments. After the tensile tests, a novel desktop-sized microscale deep drawing system is used to perform the microscale deep drawing process. A series of microscale deep drawing experiments are subsequently performed, and the experimental results indicate that an increase in the grain size results in the reduction of the deformation load of the copper sheets due to the effects of the surface grain. The results also show that the blank holder gap improves both the formability of copper sheets and the material flow.

Forming Analysis of Automotive Fender Panel Considering Die Deformation (금형 변형을 고려한 자동차 펜더패널의 성형해석)

  • Song, M.S.;Keum, Y.T.
    • Transactions of Materials Processing
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    • v.15 no.5 s.86
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    • pp.387-394
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    • 2006
  • In order to see the effect of die deformation on the forming analysis of sheet metals, the draw-ins, strains, and spring-backs of an automotive fender panels are numerically simulated by considering the die deformation found by the simultaneous structural analysis of press and dies. By coupling the forming analysis and the structural analysis, the die deformation is simultaneously taken into account in the forming process. Furthermore, for the consideration of load difference transferred among the upper die, punch, and blank holder due to the changes in sheet thickness, the gap elements are employed instead of the blank sheet in the structural analysis. The numerical simulation results of an automotive finder draw panel are compared with the measurements. The comparison of the forming and spring-back analysis results between the rigid die and the deformed die shows that the consideration of tool deformation can predict more accurately the forming and spring-back of sheet metals.

A Study on the Experimental Evaluation of the Forming Limit and Deep-Drawability of Sheet Metals (금속판재의 성형한계 및 디프드로잉 성형성의 실험적 평가에 관한 연구)

  • Rim, Jae-Kyu;Lee, Sang-Ho;Kim, Hyung-Jong
    • Journal of Industrial Technology
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    • v.19
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    • pp.67-74
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    • 1999
  • The mechanical properties including forming limit and deep-drawability of commercially-used sheet metals were experimentally estimated in this study. Uniaxial tensile test to obtain basic mechanical properties was carried out, followed by limiting dome height (LDH) test and forming limit diagram (FLD) test to quantitatively evaluate the sheet-formability. Deep drawing and reverse drawing tests were also performed to find out the critical values of the blank holding force and the gap between the die and the blank holder which enabled the deep drawing and reverse drawing of a successful cop without any wrinkle or fracture. The thickness of the cup wall along the rolling-, transeverse- and $45^{\circ}$-directions was measured and compared with one another. And the punch force-stroke curve and the critical punch force expected from the theory coincided with the experimental result very well for mild steel while not for aluminium alloy.

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