• Title/Summary/Keyword: Initial blank

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Development of Optimal Blank Shape Design Program Using the Initial Velocity of Boundary Nodes (초기 속도법을 이용한 최적 블랭크 설계 프로그램의 개발)

  • 심현보;이상헌;손기찬
    • Transactions of Materials Processing
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    • v.11 no.6
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    • pp.487-494
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    • 2002
  • A new method of optimal blank shape design using the initial nodal velocity (INOV) has been proposed for the drawings of arbitrary shaped cups. With the given information of tool shape and the final product shape, corresponding initial blank shape has been found from the motion of boundary nodes. Although the sensitivity method, the past work of the present authors, has been proved to be excellent method to find optimal blank shapes, the method has a problem that a couple of deformation analysis is required at each design step and it also exhibits an abnormal behaviors in the rigid body rotation prevailing region. In the present method INOV, only a single deformation analysis per each design stage is required. Drawings of practical products as well as oil-pan, have been chosen as the examples. At every case the optimal blank shapes have been obtained only after a few times of modification without predetermined deformation path. The deformed shape with predicted optimal blank almost coincides with the target shape at every case. Through the investigation the INOV is found to be very effective in the arbitrary shaped drawing process design.

Determination of Optimal Blank Diameter for the High Precision of Spindle Screw (고정도 Spindle Screw 전조공정에서의 최적 소재경 선정)

  • 김광호;김동환;김병민
    • Transactions of Materials Processing
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    • v.11 no.8
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    • pp.710-715
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    • 2002
  • This paper describes the numerical determination of optimum blank diameter for sound material flow and high precise thread profile of a spindle screw through external thread rolling using two-three roll dies. Initial blank diameter affects the dimensional accuracy and surface finish qualities of a spindle screw in thread rolling process, therefore it is very important to determine the optimum blank diameter in thread rolling process. In order to determine the optimum blank diameter, this paper suggests the calculation method of initial bland diameter considering the real shape of tooth. The finite element code DEFORM is applied to analyze the metal flow of tooth, and these analytical results are verified by thread rolling experiment for spindle screw.

Blank Design System for Sheet Forming (박판성형의 초기소재 설계시스템)

  • 김두현;이정민;박상후;양동열;김용환
    • Transactions of Materials Processing
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    • v.6 no.5
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    • pp.400-407
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    • 1997
  • Geometric mapping technique has been used to find the shape of initial blank for sheet forming. The method was chosen because of its simplicity and numerical efficiency. Error in blank shape were measured along deformation path by FE analysis of forming. Blank shape was modified by volume additionaddition/Subtractiontraction method with taking with taking into account of deformation path. Modified blank shape shows an acceptable result, showing the current method can be an useful tool for predicting blank shape in the practical application. More test will be done to verify the validity of the method.

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A Study on the Generation of Initial Shape for the Initiation of Optimal Blank Design Sequence (최적블랭크 설계를 위한 초기형상 생성에 관한 연구)

  • 심현보;장상득;박종규
    • Transactions of Materials Processing
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    • v.13 no.1
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    • pp.90-101
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    • 2004
  • An inverse mosaic method has been proposed to generate an initial blank shape from the final product shape. Differently from the geometric mapping method, the method can handle triangular patches. However, the generated blank shape is strongly dependent on the order of determination of nodes. In order to compensate the dependency error smoothing technique has been also developed. Although the accuracy has been improved greatly compared with the geometrical mapping method, the method has limitation, due to the no incorporation of plasticity theory. Even though the accuracy of the radius vector method is already proved. the method requires initial guess to start the method. In order to compromise the limitation of the present method and the radius vector method, the method has been connected to the radius vector method. The efficiency of the present optimal blank design method has been verified with some chosen examples.

A Development of Optimal Design Model for Initial Blank Shape Using Artificial Neural Network in Rectangular Case Forming with Large Aspect Ratio (세장비가 큰 사각케이스 성형 공정에서의 인공신경망을 적용한 초기 블랭크 형상 최적설계 모델 개발)

  • Kwak, M.J.;Park, J.W.;Park, K.T.;Kang, B.S.
    • Transactions of Materials Processing
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    • v.29 no.5
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    • pp.272-281
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    • 2020
  • As the thickness of mobile communication devices is getting thinner, the size of the internal parts is also getting smaller. Among them, the battery case requires a high-level deep drawing technique because it has a rectangular shape with a large aspect ratio. In this study, the initial blank shape was optimized to minimize earing in a multi-stage deep drawing process using an artificial neural network(ANN). There has been no reported case of applying artificial neural network technology to the initial blank optimal design for a square case with large aspect ratio. The training data for ANN were obtained though simulation, and the model reliability was verified by performing comparative study with regression model using random sample test and goodness-of-fit test. Finally, the optimal design of the initial blank shape was performed through the verified ANN model.

Determination of optimum blank diameter for the high precision of Spindle Screw (전조시 Spindle Screw의 정밀도 향상을 위한 최적 소재경 선정)

  • 김광호;김동환;김병민
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2002.05a
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    • pp.133-137
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    • 2002
  • This paper summarizes the results of a numerical study conducted to analyze the determination of optimum blank diameter on material flow and thread profile for Spindle Screw in external thread rolling. Initial blank diameter affect a quality of Spindle Screw in thread rolling process. Therefore, it is very important to determine the optimum blank diameter in thread rolling process. In order to determine the optimum blank diameter, this paper suggest the calculating method of initial blank diameter considering real shape of tooth. The finite element code DEFORM is applied to analyze the metal flow of tooth. then the analytical results are verified by experiment of thread rolling for Spindle Screw.

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A CAE Approach for Net-Shape Automobile Stamping Components of Aluminum Alloy (자동차용 알루미늄 합금 정형의 스탬핑 부품 성형을 위한 CAE기법개발)

  • 최한호
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1999.03b
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    • pp.45-48
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    • 1999
  • A program for initial blank design in sheet forming which contains the capabilities of forward loading simulation by the finite element method and backward tracking simulation has been developed and proved the effectiveness by applying to a square cup stamping process. In the blank design of square cup stamping the backward tracing program can produce an optimum blank configuration which forms a sound net-shape cup produce without machining after forming. Another general application appears in the blank design of a cup stamping with protruding flanges one of typical automobile components. The blank configurations derived by backward tracing simulation have been confirmed by a series of loading simulations. The approach for decision of an initial blank configuration presented in this study will be a milestone in fields of sheet forming process design.

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Verification of Sensitivity Method for the Design of Optimal Blanks of General Shaped Parts (일반적인 형상의 스탬핑의 최적블랭크 설계를 통한 민감도법의 검증)

  • 손기찬;심현보;황현태
    • Transactions of Materials Processing
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    • v.10 no.1
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    • pp.15-22
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    • 2001
  • The sensitivity method has been utilized to find initial blank shapes which transform into desired shapes after forming. From the information of die shapes, target shape and material properties, the corresponding initial blank which gives final shape after deformation has been found. Drawings of a trapezoidal cup, a cross-shaped cup and an oil pan have been chosen as the examples. At every case the optimal blank shape has been obtained only a few times of modification without any predetermined deformation path. With the predicted optimal blank, both computer simulation and experiment are performed. Excellent agreements are recognized between simulation and experiment at every cases Through the investigation, the sensitivity method is found to be effective in obtaining optimal blank shapes in drawing of complex shapes.

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Blank Design for Optimized Thickness Distribution for Axi-symmetric Superplastic Blow Forming (축대칭 초소성 블로성형의 두께분포 최적화를 위한 블랭크 설계)

  • 이정민;홍성석;김용환
    • Transactions of Materials Processing
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    • v.8 no.1
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    • pp.92-100
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    • 1999
  • A procedure is proposed for determining the initial thickness distribution in oder to produce a specified final thickness distribution for the axisymmetrical superplastic blow forming processes. Weighted parameter is introduced to improve the simple ad $d_traction method and the initial blank thickness distribution is obtained by optimizing the weighted parameter. This method is applied to superplastic free bulging process with the uniform thickness distribution of final shape to confirm its validity. The optimum initial blank thickness distributions is obtained from arbitrary axisymmetrical superplastic blow forming processes such as dome, cone and cylindrical cup forming with die contact. It is concluded that the ad $d_traction method with weighted parameter is an effective method for an optimum blank thickness distribution design.esign.

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Study of Forming Analyzing Auto-body panel by Using One-step Finite Element Method (One-Step 유한요소법을 이용한 차체판넬 성형해석에 관한 연구)

  • Jung, D.W.;Lee, C.H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2006.05a
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    • pp.261-264
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    • 2006
  • Many process parameters have an effect on the auto-body panel forming process. A well-designed blank shape causes the material to flow smoothly, reduces the punch and yields a product with uniform thickness distribution. Therefore, the determination of an initial blank shape plays the important role of saving time and cost in the auto-body panel forming process. For these reasons, some approaches to estimate the initial blank shape have been implemented in this paper, the one-step approach by using a finite element inverse method will be introduced to predict the initial blank shape the developed program is applied to auto-body panel forming.

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