• Journal of the Korean Society for Precision Engineering
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• v.13 no.9
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• pp.46-53
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• 1996

This paper describes some research works of computer-aided design of blanking and piercing for stator and rotor parts and irregularly shaped sheet metal by press. An approach to the system is based on knowledge based rules. The process planning system by considering a blank layout for nesting of irregularly shaped sheet metal and an improved strip layout for stator and rotor parts and irregularly shaped sheet metal is implemented. Using this system, design parameters(utilization ratio, slitting width, pitch, working order, die blank shapes) are determined and output is generated in graphic forms. Knowledges for blank layout and strip layout are extracted from the plasticity theories, handbooks, relevant references and empirical know-hows of experts in blanking companies. The implemented system provides powerful capabilities for process planning of stator and rotor parts and irregularly shaped sheet metal.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.04a
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• pp.146-150
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• 2000

there are a lot of process variable exerted influence on the formability of products in deep drawing process. Particularly it is important that blank shape of the process variables. A paper to be connected with process variables of elliptical deep drawing products is insufficient the actual circumstances enough though researches have been performed on the deep drawing of sheet metal forming. In this study The effects of thickness distribution and movement of sheet are grasped as alteration of blank shapes in the process of elliptical deep drawing product and then optimal blank shape was presented. They were verified by the finite element analysis (FEA) and experiment.

• 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.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.4
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• pp.31-36
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• 2008

Sheet metal forming has some merits that are less loss of materials in process, less time-consuming and it makes mass product possible. The product produced by sheet metal forming process has high strength compared to the weight and better surface characteristics. Therefore, sheet metal forming process is a lot used in automobiles, aircrafts, electronics and appliances. This paper made the process design for forming Bracket Front Back Frame Lower, determined the blank shape and size using PAM-STAMP, commercial software and evaluated formability. It has been proved that the optimal blank through the result forming analysis has advantage in terms of formability and spring back compared to the rectangular blank.

• Transactions of Materials Processing
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• v.4 no.4
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• pp.302-321
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• 1995

A method of determining an optimum blank shape for the non-circular deep drawing process is investigated. The rigid-plastic finite element method is introduced and the computer program code is developed. The ideal shape of a drawn cup with uniform wall height is assumed and metal flow is traced back-ward step by step to predict an initial blank shape of the ideal cup. For examples of the non-circular deep drawing products, three cases of drawn cup with quadrilateral punch shape are considered and optimum blank shapes for each case are proposed and compared with experimental results.

• 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.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.10a
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• pp.89-92
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• 1997

Design of a weld line in a tailor welded blank is indispensable for good manufacturing of stamped parts as assigned, since the intial weld line is distorted severely with forming. The initial weld line has to be determined such that desired weld line in a formed part can be obtained. The initial weld line was predicted by inverse finite element analysis from the desired weld line in a formed part. The inverse approach is applied to the cylindrical and square cup drawing with tailor welded blanks. The applications demonstrates that the approach is useful for design of weld line of tailor welded blank.

• Transactions of Materials Processing
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• v.8 no.6
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• pp.541-553
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• 1999

Cold forging is a special type of forging process in which metal is forced to flow plastically under compressive force into a variety of shapes in room temperature. Gear blank, which is produced by cold forging, is concerned with the production method of transmission gear. Based on the results of simulation of the current four-stage process, the gear blank forging process for improving the conventional process sequence is designed. The rigid plastic finite element analysis for improving the conventional process. The new process consists of three stage operations with one annealing treatment after first operation. Based on the results of simulation of the proposed process, a required equipment could be selected. The new designed process appears to be more economical in producing the gear blank.

• Transactions of Materials Processing
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• v.5 no.4
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• pp.281-287
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• 1996

Two kinds of blank shapes optimum and square are adopted to investigate formability. Optimum blank shape is determined to construct an L-shape cup with uniform height and without flange part. For this purpose rigid-plastic FEM analysis is applied with backward tracing technique. Maximum cup depth and strain distribution are measured experimentally for the products of the two kinds of blank shapes which are optimum and square. it is confirmed that deeper cup without severe thickness reduction can be obtained from the optimum shape.

• Transactions of Materials Processing
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• v.24 no.1
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• pp.28-36
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• 2015

After a short review of the iterative optimal blank method, a new method of measuring the shape error for stamped parts with 3D contour lines, which is an essential component of the optimal blank design, is proposed. When the contour line of the target shape does not exist in a plane, but exists in 3D space, especially when the shape of the target contour line is very complicated as in the real automotive parts, then the measurement of the shape error is critical. In the current study, a method of shape error measurement based on the minimum distance is suggested as an evolution of the radius vector method. With the proposed method, the optimal blank shapes of real automotive parts were found and compared to the results of the radius vector method. From the current investigation the new method is found to resolve the issues with the radius vector method.