• Journal of the Korean Society for Precision Engineering
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• v.16 no.2 s.95
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• pp.87-94
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• 1999

The automated die design program is developed for cold forging of axisymmetric parts which are mainly produced by forward extrusion, backward extrusion, composite extrusion and upsetting. For this study, firstly classification of forged parts and investigation of die construction type usually employed in forging industry are carried out and the most proper type from several kinds of die construction is proposed as a standardized one. Based on the die design rules summarized in the references such as handbooks, technical papers, monthly journals, etc. the automated die design program was made using AutoLISP language available in AutoCAD software of personal computer. This program interactively runs for only input data, for example, forging process, shape of forged parts, type of punch, split of die insert and design of shrinkage rings and then displays details of drawings necessary to make a forging die. When a variety of forging processes and forged parts are tested to examine the validity of this program, it was confirmed to give good results applicable to the forging die design in press shop.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.143-147
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• 2005

In this study, a die set for enclosed die forging is developed and it is applied to precision forging of bevel gears and spiders. The enclosed die forging die set is introduced in detail together with the enclosed die forging. A target mechanical press and a model product are selected and various engineering technologies are applied for detail design of the enclosed die forging die set. Several precision forgings are manufactured by the developed die set. The enclosed die forging die set as well as the precision forging processes are developed under intensive industry-university cooperation.

• Transactions of Materials Processing
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• v.27 no.3
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• pp.165-170
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• 2018

In order to increase the lifetimes of cold forging dies, insert rings are generally used. In this study, an insert ring and shrunk ring of the flange upsetting die were designed for the cold forging of an automotive wheel nut. The Stress distribution occurring in the die during forging was simulated using a commercial finite element analyzing program. The effects of the fitting interference and inclined angle of the insert ring on the compressive stress of the die inside were also investigated. The simulated data were compared with the real lifetimes of the forging dies. The maximum compressive stress acting on the edge of a forging die should have the most influence on die lifetime, an idea which could help develop the die design with the longest lifetime. The design of the most optimal forging die with the longest lifetime is made possible by analyzing the maximum inner pressure and principal stress between the shrunk ring and insert ring.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.1
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• pp.59-65
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• 2004

Hollow flange-shaped parts rue widely used in transportation systems. For good quality products, in general, design of preforms and die shapes for a progressive forging process is an important issue. For the design of die shapes for the forging process of a hollow flange, computer simulations Were earned out using the rigid-plastic finite element method. Forging defects like folding were seen in the vicinity of die corners at the typical shape ratios of upper and lower dies Die shape ratios at which the forging defect could occur during the extrusion-forging process of the hollow flange were investigated. The results might be efficiently used for the proper design of perform shapes, die shapes, and forging processes.

• 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.

• Transactions of Materials Processing
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• v.1 no.1
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• pp.20-32
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• 1992

This paper describes some research of Computer-Aided Process Planning and Die Design of Hot Forging for axisymmetric parts produced by the press. An approach to the system is based on knowledge based system. The system has been written in AutoLisp with personal computer. Knowledges for process planning & die design are extracted from the plasticity theories, handbooks, relevent references and empirical know-how of field experts in hot forging companies. The developed system is composed of five main modules, such as input module, process planning module, die design module, flow simulation module and output module which are used independently or in all. The final output is generated in graphic from. The developed system which aids designer provides powerful capabilities for process planning and die design of hot forging. This system also provides approximate flow pattern.

• Transactions of Materials Processing
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• v.31 no.2
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• pp.51-56
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• 2022

In this study, finite element analyses were performed by applying a stress ring and split die design to relieve the tensile stress acting on the die due to high surface pressure during warm-closed forging. The applied material was a yield-ratio-control-steel (YRCS). It was used without quenching or tempering after forging. In the case of stress rings design, the number of stress rings and the tolerance for shrink fit were different. Vertical and horizontal splits were applied for insert die split design. Case 5 die with three stress rings, 0.2 % shrink fit tolerance, and vertical split was selected as an effective die design for tensile stress reduction. Based on die stress reduction analyses, Case 5 die for warm-closed forging was produced and smooth forgeability was secured, making it possible to manufacture forging product of yoke with the required geometry. In addition, controlled cooling using warm forging heat was applied to secure mechanical properties of yokes. When oil cooling was used for direct controlled cooling after warm-closed forging, a relatively uniform Rockwell hardness distribution and high mechanical properties could be obtained.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.2
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• pp.104-109
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• 1994

This research describes some developments of computer-aided process planning and die design for hot forging products of H-shaped plane strain produced by the press. The system is composed of three main modules(process planning module, die design module and simulation module) which are used independently or in all. Systm capabilities include as follows: 1. In die design module, using the results of process planning module, the shape and size of bolcker and finish die in each operation are determined and the ouput id generated in graphic form for manufacturing drawing. 3. In simulation module, the flow pattern of workpiece and the load/stroke curve are approximately predicted. Design rules for process planning and die design are extracted from plasticity theories, handbooks, relevant references and empirical know-how of field experts in hot forging companies. The developed system provides poweful capabilities for process planning and die design of hot forging products.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.19-22
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• 2003

In this study, the design of prestressed die for spur gear forging have been investigated. The stress concentration at notch of the die insert is very important in the design of die for the forging of spur gear such as non-axisymmetric geometry. In the previous study, the flexible tolerance method was used in order to search the optimal value of design variables considering the constrain conditions. In the design process, it was also involved the safety factor to the yield strength of each ring by considering allowable tensile or compressive hoop stress in each ring. Using this technique, the die deign for spur gear forging has been successfully performed without yielding of the die after shrink fitting and during forging.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.1
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• pp.33-41
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• 2010

This study was aimed at the design of the dies for the unified pipe joint of the intermediate shaft using the computer simulation to shorten the period of production, on the basis of the process planning which was designed by the field experts. In the computer simulation, 'Deform-3d' and 'eesy-DieOpt' have been used, which are the commercial process analysis and die design program. Through the process analysis, we could know the propriety of the forming process, the inner pressure of the die and the suitable fitting pressure between the insert and the sleeve which was not showing any positive tangential stresses in the insert. Through the simulation of die design, we could know the number of the stress ring, the diameter ratios, the stresses of the die, the shrink fitting tolerance and temperature in the condition of the already determined maximum outer die diameter of the multi-stage former. The validity of the die design using the computer simulation was analyzed by the experiments and the results were satisfactory. As the results of this study, the new and easy die design system for multi-forging has been developed.