• Transactions of Materials Processing
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• v.9 no.5
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• pp.526-532
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• 2000

Springback simulation is receiving increasing attention throughout the automotive industry and the academic world. The knowledge of the real springback of stamped parts can help the stamping technicians to modify the process parameters or die geometry in order to reduce the shape defect. This paper presents the results of springback simulation after aluminium square cup deep drawing and trimming simulation, and results of springback optimization using response surface method.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.57-61
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• 1999

Springback after forming is the critical factor affecting the product quality. It is very difficult to predict the amount of springback not only because of complex geometry and material characteristics of the stamping product but because the methodology has not been established. In this study springback mechanism is introduced and experimental tryout and computer simulation are carried out for die design of automotive rear side frame. Futher springback was verified by comparing the result of computer simulation with the measured tryout result.

• Journal of Industrial Technology
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• v.18
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• pp.217-223
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• 1998

The springback characteristics of some sheet metals such as commercially pure aluminium, mild steel and stainless steel in a forming process are investigated experimentally. Three geometrical parameters for evaluating springback in the plane-strain draw-bending, which was a benchmark model of NUMISHEET '93 conference, are defined. The measurement of the springback parameters is carried out accurately and easily by using an image analysis system developed in this study. The effects of the blank holding pressure and tensile strength of the material on the springback are also examined.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.342-342
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• 2005

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.418-421
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• 2001

Press brake is used as bending and forming sheet metal in vehicle and many kind of industry. This paper deals with development of NC press brake based on high precision positioning device and software, which can be operated on personal computer. In this system, positioning device is used for controlling bending angle and operated by the developed software, which is database from material property, width and thickness of material. This study will make distribution in development of computer aided press brake.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.1
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• pp.42-49
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• 2016

This study was analyed V-bending in order to analyze the spring-back phenomenon in the roll forming process. The material of forming sheet used in the roll forming process is high tension steel and the product name of sheet material is POSTEN 60. The most important variable is the number of roll passes (3-Pass, 4-Pass, 5-Pass, 6-Pass and 10-Pass) and other roll forming process variables were fixed. To determine the characteristics of the tension and compression, the forming sheet was analyzed by dividing the layer (Upper and Bottom) in the thickness direction from the center line. The results of FEM simulation analysis was derived to von-mises stress equivalent strain, and the spring-back value was calculated according to the final forming shape. The more number of the roll pass, von-mises stress and equivalent strain value of forming sheet were lowed. Also, spring-back values tended to decrease. The results of this study can be utilized for prediction and trend of spring-back value in the roll forming process applied to high tension steel sheet. So, development time and cost of the roll forming process is expected to be reduced.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.450-455
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• 2017

A shield connector is an automotive electrical component that is used to connect electrical wiring in a vehicle. This part is made by progressive pressing using a phosphor bronze material with high electrical conductivity. The shape of the product is not complicated, but plastic forming techniques are required, such as deep drawing and bending, as well as shearing techniques such as piercing and notching. The finite element method was used to model the process. The strip layout design stage of the progressive die makes it possible to examine the thickness change, the stability of the forming process, and the spring-back. As a result of this analysis, it is possible to predict the correction values for the tendency of cracks, wrinkles, and incomplete plastic deformation, and to identify possible problems in advance. As a countermeasure against the forming error caused by the drawing process analysis, the drawing shape was modified and applied in the process design. For effective material utilization, a 3D strip layout was designed using an optimized blank shape based on nesting. The results improve the crack stability and spring-back of shield connector products produced through progressive pressing.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.106-109
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• 2005

Springback is a common phenomenon in sheet metal forming, caused by the elastic recovery of the internal stresses after removal of the tooling. Recently, advanced high strength steels (AHSS) such as TRIP and DP are finding acceptance in the automotive industry because their superior strength to weight ratio can lead to improved fuel efficiency and assessed crashworthiness of vehicles. The major troubles of the automotive structural members stamped with high strength steel sheets are the tendency of the large amount of springback due to the high yield strength and the tensile strength. The amount of springback is mainly influenced by the type of the yield function and anisotropic model induced by rolling. The discrepancy of the deep drawn product comparing the data of from the product design induced by springback must be compensated at the tool design stage in order to guarantee its function and assembly with other parts. The methodology of compensation of the low shape accuracy induced by large amount of springback is developed by the expert engineer in the industry. Recently, the numerical analysis is introduced in order to predict the amount of springback and to improve the shape accuracy prior to tryout stage of press working. In this paper, the tendency of springback is evaluated with respect to the blank material. The stamping process is analyzed fur the front side member formed with AHSS sheets such as TRIP60 and DP60. The analysis procedure fully covers the binderwrap, stamping, trimming and springback process with the commercial elasto-plastic finite element code LS-DYNA3D.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.302-305
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• 2007

The springback characteristics of AZ31B magnesium alloy sheet was investigated in OSU draw/bend test. Springback is the elastically-driven change of shape of a part after forming and it should be estimated and controlled to manufacture more precise products in sheet forming. The demands are increasing for magnesium alloy sheet press forming, but the study on its springback characteristics is insufficient. Strip draw/bend tests were conducted with various conditions - die radius, sheet thickness and controlled tensile force. The springback angles were measured from 'sidewall curl' of deformed shape. The tendency of springback angle was observed from the tests.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.162-168
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• 2008

Recently surround molding parts using stainless steel are applied to international and domestic high grade vehicles, but there are great difficulties in die manufacture because of springback and twist after forming process. To solve this problem, finding the method of reduction springback is very important. In this study the springback which might happen during making a die that produce stainless steel surround molding parts is predicted and the geometry of die which satisfy the tolerance between product and panel after forming and springback will be suggested using automatic die compensation module.