• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.414-417
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• 2005

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.

• Transactions of Materials Processing
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• v.9 no.6
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• pp.598-603
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• 2000

In order to improve trial-and-error based conventional practices for optimizing forming processes, a direct design method to guide iterative design practices, called the ideal forming theory, has been previously developed. In the theory, material elements are required to deform following the minimum Plastic work Path. The theory can be used to determine the ideal initial blank shape needed to best achieve a specified final shape while resulting in optimum strain distributions. In this work, the direct design method based on the ideal forming theory was applied to design initial design shape for VCR deck chassis. Based on the solution of the ideal forming theory, FEM analysis was utilized to evaluate an optimum blank shape to be formed without tearing. Simulation results are in good agreement with experimental data. It was shown that the proposed sequential design procedure based on direct design method and FEM can be successfully applied to optimize the die design Procedure of sheet metal forming processes.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.419-422
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• 2005

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.

• Transactions of Materials Processing
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• v.9 no.4
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• pp.348-355
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• 2000

The backward tracing scheme(BWT) of the finite element method has been extended lot the design of sheet blank in three-dimensional deformation. Originally the scheme was developed for preform design in bulk forming, and applied to several forming processes successfully. Its key concept is to trace backward from the final desirable configuration to an intermediate preform or initial blocker. A program for initial blank design in sheet forming which contains the capabilities of forward loading simulation by the finite element method and backward tracing 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 product without machining after forming. For the confirmation of the analytic result derived from the backward tracing simulations as well as forward loading simulations, a series of experiment were carried out. The experiments include the first trial sheet forming process with a rectangular blank, an improved process with a modified blank preform and the final process with an optimum blank resulted from the backward tracing scheme. The experiments show that the backward tracing scheme has been implemented successfully in blank design of sheet metal forming.

• Transactions of Materials Processing
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• v.10 no.4
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• pp.283-293
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• 2001

Laser welded tailored blanks(TB) are increasingly used in automotive parts. Among these, TB side panel has forming difficulties in stretch flanging areas such as front and center pillar lower region. To avoid splits in the stretch flanging areas, Proper design of blank shape and drawbeads are essential In this study, the forming simulaton is carried out to investigate the influences of blank shape and drawbeads on stretch flange formability of different thickness TB. And an optimization procedure including the effects of both the blank design and drawbeads is presented. The optimization procedure proposed in this study is expected to be effectively used in blank and die design of TB side panel.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.59-62
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• 2001

Welded blank hydroforming technology is applied to an automotive subframe which has been manufactured by stamping and welding processes. Blank shape and die system is suggested on the basis of finite element analyses. Various defects, especially wrinkling problems in the area of sudden section change, are investigated, analyzed and tried out. The blank shape and the die system are modified to get the sound welded blank hydroformed subframe.

• 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.

• 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.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.5
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• pp.93-99
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• 2016

The trimming process is required for satisfying the dimensions of a final product in the hot stamping process. In general, the mechanical trimming or laser trimming process is applied after hot stamping. However, these processes have several disadvantages such as short tool life and low productivity. Therefore, in this study, the optimal trimless blank shape for the hot stamping process of a sill side was designed to remove the trimming process after hot stamping. In order to design the trimless blank, numerical analysis was performed. Firstly, CFD analysis was carried out to predict the cooling temperature and holding time of the hot stamping process. Then, the optimal trimless blank shape was determined through FE analysis. The effectiveness of the designed trimless blank shape was verified through a hot stamping experiment at an actual industrial site.

• Journal of Ocean Engineering and Technology
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• v.13 no.3 s.33
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• pp.12-20
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• 1999

In this paper, method for mapping a three-dimensional shape into the two-dimensional plane will be introduced. This method is referred to geometric modelling and means a transformation between the flat sheet and final surface. The initial blank shape represents the original configuration of the final shape formed into three dimensional surface. The initial constant constant area mapping hypothesis was used in this paper. This technique will be applied to the basic data for an interactive computer design capable of dealing with typical stamping process, including deep parts and complex shapes.