• International Journal of Precision Engineering and Manufacturing
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• v.3 no.4
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• pp.37-42
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• 2002

The purpose of this paper is comparing the forging effect according to the shape of preforms of cup shaped powder forging product, and extending the application of powder forging technology to more complicated cup-shaped products like pistons. In order to achieve this, preforms are provided by compacting, sintering, and machining to 5 different shapes, then forged to the final shape of products. The workability for sintered aluminium powder material was examined and confirmed its slope was 0.5 as known. Density and strain loci of forged products are also evaluated and compared. On the basis of the results, the most effective shape of preform was proposed. The preform for the piston which is 50mm in diameter was prepared and hot forged successfully to the final product.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.178-182
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• 1995

The technique of neural networks is applied to cold forging design system. A user can select more desirable plans in cold forging design by being advised with expert's opinion from neural networks. The neural networks are learned with 3 parts which are most important in cold forging design-undercut, narrow hole, sharp corner. Using the neural networks, the cold forging design system built in this study determines forming possibility about variable shapes in product. We can get available result using the system.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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• pp.158-162
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• 2002

In this paper, the usefulness of a three-dimensional forging simulation technique is verified through its application to process design in rotor pole forging. A simulator, AFDEX3D developed based on the rigid-plastic finite element method and hexahedral elements, is employed. The simulated results of an application example found in a precision forging company are compared with the actually forged ones in detail. It has been verified that the simulation results are in good agreement with the actual phenomena.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.932-936
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• 1997

In order to increase the productivity of electrical parts, manufacturing processes using progressive die have been widely used in the industry. If closed-die forging process may be included in the series of the forming process, however, there arise many problems in the die design, such as determination of blank size, feeding method and formability, etc. For the proper design of a process, a prediction of the process is requred to obtain many design parameters. In this work, three-dimensional rigid-plastic finite element analysis is carried out to simulate precision forging process. The forging process of STEM, a part of photo pick-up hologram device, is simulated with the two types of processes, open die forging and semi-closed die forging, respectively. Form the results of analyses, the forging processes can be predicted successfully, which enables to design appropriately the die and the process.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1996.10a
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• pp.113-121
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• 1996

AI7075 alloy has been used for aircraft components since it has the advantage of high strength, high toughness, and high corrosion resistance. Many airframe components consist of various combinations of rib-web structure. In this study, various process paramenters such as die design, lubricant, ram speed, forging temperature have been investigated using the experiment and F.E.M. simulation to develop the precision forging technology for AI7075. When lubricant is applied to both material and die, shear friction factor is 0.1 which shows best effect of lubricant. It is specific corner radius of die that minimized forging load regarding process conditions, especially according to the ratio of the width of rib and web. In conclusion, optimum corner radius is 2~3mm when the width of rib and web is 3mm and 20mm respectively.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1513-1516
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• 2003

A crank throw, which is one of the crankshaft part for a large diesel engine is manufactured by closed die forging or open die forging. For the purpose of improvement of productivity the open die forging is usually adopted these days. However it has disadvantage of low yield ratio compare to closed die forging. To overcome this problem, the material properties for hot top and bottom zones of ingot are investigated to utilize them to the product and a modified forging process to reduce the material loss of ingot body through forging analysis according to forging factors(a , R, Ø$\sub$B/, Ø$\sub$D/) is suggested.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.397-398
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.209-210
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.183-186
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• 1995

A simulation method basee on upper bound method is developed in order to characterize forging characters in forging of spur gears. In this paer, utlizing a kinematically admissible velocity field and applying it to study the effect of inner diameter of holow billet. To predict the variation of inner diameter of hollow billet, neutal surface has been introduced into forging of hollow gears from hollow billes with flat punch. The neutral surface of each step is assumed as a circle and determined in order to have minimum forging energy by golden section method. According to the analysis, the magnitude of inner diameter of initial billet is vary important to reduce the relative pressure and forging load. And the variation of inner diameter of billet during spur gear forging is successfully predicted.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.933-934
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• 2012