• Title/Summary/Keyword: Draw-bead restraining force

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Simulation-based Prediction Model of Draw-bead Restraining Force and Its Application to Sheet Metal Forming Process (유한요소법을 이용한 드로우비드 저항력 예측모델 개발 및 성형공정에의 적용)

  • Bae, G.H.;Song, J.H.;Huh, H.;Kim, S.H.;Park, S.H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2006.06a
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    • pp.55-60
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    • 2006
  • Draw-bead is applied to control the material flow in a stamping process and improve the product quality by controlling the draw-bead restraining force (DBRF). Actual die design depends mostly on the trial-and-error method without calculating the optimum DBRF. Die design with the predicted value of DBRF can be utilized at the tryout stage effectively reducing the cost of the product development. For the prediction of DBRF, a simulation-based prediction model of the circular draw-bead is developed using the Box-Behnken design with selected shape parameters such as the bead height, the shoulder radius and the sheet thickness. The value of DBRF obtained from each design case by analysis is approximated by a second order regression equation. This equation can be utilized to the calculation of the restraining force and the determination of the draw-bead shape as a prediction model. For the evaluation of the prediction model, the optimum design of DBRF in sheet metal forming is carried out using response surface methodology. The suitable type of the draw-bead is suggested based on the optimum values of DBRF. The prediction model of the circular draw-bead proposes the design method of the draw-bead shape. The present procedure provides a guideline in the tool design stage for sheet metal forming to reduce the cost of the product development.

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Development of Drawbead Expert Models for Finite Element Analysis of Sheet Metal Forming Processes(Part 2:Modeling) (박판성형공정의 유한요소해석을 위한 드로우비드 전문모델 개발(2부: 모델링))

  • Keum, Yeong-Tak;Lee, Jae-U
    • Transactions of Materials Processing
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    • v.7 no.1
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    • pp.12-22
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    • 1998
  • An expert drawbead model is developed for the finite element analysis of stamping processes. The expert model calculates drawbead restraining forces and bead-exit thinnings with the forming condi-tions and drawbead size. The drawbead restraining forces and bead-exit thinnings of a circular draw-bead and stepped drawbead are computed by mathematical models and corrected by the multiple lin-ear regression method based on experimental measurements. The squared drawbead preventing the sheet from drawing-in inside die cavity is assumed to have a very huge drawbead restraining force and no pre-strain just after drawbead. The combined beads are considered as a combination of basic draw-beads such as circular a drawbead stepped drawbead and squared drawbead so that the drawbead restraining forces and bead-exit thinnigs are basically sum of those of basic drawbeads.

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A Study on the Influence of the Punch Stroke of Bead on the Draw-bead process by using Static-explicit Finite Element Method (정적 외연적 유한요소법을 이용한 비드 펀치 행정거리가 드로우비드 공정에 미치는 영향에 관한 연구)

  • 정동원
    • Journal of Ocean Engineering and Technology
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    • v.15 no.2
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    • pp.72-78
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    • 2001
  • The bead is used to provide properly restraining force in the sheet metal forming process. This bead process includes bending and geometrical non-linearity, and affects the state of binderwrap. Therefore, the analysis of bead process is very important to obtain the desired formability. In this paper, the research about the influence of the punch stroke of bead on the draw-bead process was conducted. Results from the analysis will give useful information to the effective tool design of blank forming process. To analyze the bead process, and elasto-plastic finite element formulation is constructed from the equilibrium equation and the considered boundary conditions involved a proper contact condition. The static-explicit finite element method as a numerical method for the analysis was applied to the analysis program code. It was found that this method could solve too much computation time and convergence problem owing to high non-linearity of bead forming process.

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Study on Design Parameters in a Stamping Process of an Automotive Member with the Simulation-based Approach (해석적인 방법을 이용한 복잡한 형상의 자동차 부재 스탬핑 공정에서의 주요 설계인자 연구)

  • Song J. H.;Kim S. H.;Kim S. H.;Huh H.
    • Transactions of Materials Processing
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    • v.14 no.1 s.73
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    • pp.21-28
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    • 2005
  • This paper is concerned with the quantitative effect of design parameters on a stamped part of the auto-body. The considered parameters in this paper are the blank holding force, the draw-bead force, the blank size which greatly affect the metal flow during stamping. The indicators of formability selected in this paper are failures such as tearing, wrinkling and the amount of springback. The stamping process of the front side inner member is simulated using the finite element analysis changing the design parameters. The numerical results demonstrate that the blank holding force cannot control the local metal flow during forming although it controls the overall metal flow. The modification of the initial blank size considering the punch opening line ensures the local wrinkling and reduces the amount of springback after forming. The restraining force of draw-bead controls the metal flow in the local area and reduces the amount of excess metal. It is noted that the parametric study of design parameters such as blank holding force, the blank size and the draw-bead are very important in the process design of the complicated member.

An Angle-Binder Drawbead Simulator for Measuring Drawbead Forces on Inclined Binder Surface (경사진 바인더면의 드로우비드력을 측정하기 위한 모의실험장치)

  • Yang, W.H.;Choi, K.Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2009.05a
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    • pp.180-184
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    • 2009
  • A novel set of experimental test tooling for measuring pulling and holding forces for drawbeads on binders inclined at a wide range of angles is introduced. A mechanical design featuring a single load cell, a male-female draw bead set, translation and rotation degrees of freedom, and a screw-driven clamping system has been incorporated into a standard tensile test machine. On a real time basis, restraining and holding force data with respect to draw-in displacement may be directly downloaded into a PC for data processing. The proposed experimental system represents a significant breakthrough in drawbead simulation technology due to its relatively low cost, clever design, and versatility. The system is shown to yield excellent experimental data suitable for verifying theory and numerical model predictions.

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Analysis-based Die Face Design for the Improvement of Surface Quality for a Heat Protect Panel of an Automobile (차량용 열차단판의 면품질 개선을 위한 성형해석 기반 금형면 설계)

  • Kim, K.P.;Kim, S.H.;Lee, D.G.;Jang, K.C.
    • Transactions of Materials Processing
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    • v.17 no.4
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    • pp.278-283
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    • 2008
  • This paper concerns the die face design for a heat protect panel aided by the finite element forming analysis in order to eliminate the surface defect and to improve the surface quality. The CAE procedure of the stamping process is introduced in order to reveal the reason of surface inferiorities and to improve surface quality. Complicated shape of the product induces the surface inferiorities such as wrinkling due to the insufficient restraining force of the forming blank and the non-uniform contact of the blank with the tools. This paper proposes a new guideline for the die design which includes the modification of tool shapes and addition of the draw-beads on the tool surface for ensuring the increased the restraining force with the uniform contact condition. The effectiveness of the proposed design is verified by the forming analysis and is confirmed by the tryout operation in the press shop. The analysis and test results show that the modified process parameters such as tool shapes and draw-beads can reduce the tendency of wrinkling and improve surface quality.

A Study on the 2-Layered Sheet Metal Forming Analysis and Applications in Automotive Exhaust Component (2-Layer 블랭크를 적용한 자동차 배기 부품의 박판 성형 해석 및 적용)

  • Roh G. T.;Jeong W. S.;Moon M. S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.10a
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    • pp.318-321
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    • 2005
  • The shell part is made of 2-layered blank because of functional requirements. To investigate the draw formability in this kind of part, the 2-layered sheet metal forming analysis process should be stipulated. First of all, treatment of contact with each blank must be considered to prevent the penetration on the each blank. Subsequently, applying the draw bead force is considered carefully because application of drawbead force for analysis is different with equivalent drawbead force. Formability as like crack, neck and wrinkles is estimated by FLD(Forming Limit Diagram) and thinning. A feasibility of the 2-layered sheet metal forming analysis process study is verified compare 2-layered sheet metal forming analysis with experimental results.

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The Analysis of Draw-bead Process by Using Static-explicit Finite Element Method (정적 외연적 유한요소법을 이용한 비드공정해석)

  • Jung, Dong-Won
    • Proceedings of the KSME Conference
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    • 2001.06c
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    • pp.604-609
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    • 2001
  • In the sheet metal forming process, the drawbead is used to control the flow of material during the forming process. The drawbead provides proper restraining force to the material and prevents defects such as wrinkling or breakage. For these reasons, many studies for designing the effective drawbead have been conducted. For the analysis, the numerical method called the static-explicit finite element method was used. The finite element analysis code for this method has been developed and applied to the drawbead process problems. In result, convergence problem and computation time due to large non-linearity in the existing numerical analysis methods were no longer a critical problem. Futhermore, this approach could treat the contact friction problem easily by applying very small time intervals. It is expected that various results from the numerical analysis will give very useful information for the design of tools in sheet metal forming process.

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The Analysis of Draw-bead Process According to the Effect of the Drawbead Shape by Using Static-explicit Finite Element Method (정적 외연적 유한요소법을 이용한 드로우비드 형상에 따른 비드공정 해석)

  • 정동원
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2001.10a
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    • pp.275-281
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    • 2001
  • In the sheet metal forming process, the drawbead is used to control the flow of material during the forming process. The drawbead provides proper restraining force to the material and prevents defects such as wrinkling or breakage. For these reasons, many studies for designing the effective drawbead have been conducted. In this paper, the effect of the drawbead shape will be introduced. For the analysis, the numerical method called the static-explicit finite element method was used. The finite element analysis code for this method has been developed and applied to the drawbead process problems. In result, convergence problem and computation time due to large non-linearity in the existing numerical analysis methods were no longer a critial Problem. Futhermore, this approach could treat the contact friction problem easily by applying very small time intervals. It is expected that various results from the numerical analysis will give very useful information for the design of tools in sheet metal forming process.

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A Study on the Binding Force of Drawbead in the Sheet Metal Forming Process through the finite element and experimental analysis (해석과 실험을 통한 박판성형공정에서의 드로오비드의 구속력에 관한 연구)

  • Bahn, Gab-su;Mo, Chang-ki;Suh, Eui-kwon
    • Journal of the Korean Society of Industry Convergence
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    • v.10 no.1
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    • pp.5-14
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    • 2007
  • It is necessary for development of drawing product with press to have suitable material selection & all process design and the problem during press process has been cleared from judgement of experience & trial and error. Recently we can estimate press process result from computer aided design & FEM. But we can get more reliable result when we can put more precise process variants during FEM. In case of using a drawbead that is used for the material inflow, it is considered for us to put material property, other analysis condition & friction figure when material is passing through the drawbead for better FEM. From our study, we have drawn an analogy bead connection depth, friction figure & drawing and restraining load according to kinds of lubrication from experiment & FEM for the drawbead. We applied above result to the drawing experiment & FEM and confirmed the validity. We could notice the relation between friction figure & drawing load and the friction figure variation according to kinds of lubrication. It is expected to draw more precise analogy that can be used for real process due to more precise process variants application to FEM.

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