• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.19 no.5
• /
• pp.91-97
• /
• 2020

A split-die design for the cold forging of symmetric parts such as those having a hexagonal cross-section is presented in this paper. Parts with a hexagonal cross-section, such as bolt heads and nuts, should be forged with a die that has a hexagonal-shaped hole. A split type die is required to mitigate the buildup of stress concentrations located at the corners of the hexagonal hole. Generally, the insert of a hexagonal die is made by cutting each corner of a cylinder using a hexagonal hole and then combined with the die and shrink-fitted. However, split dies face problems when extruding material at the corners of the hexagonal split die. To address this problem, two types of split dies were evaluated: rounded hexagonal dies and angular hexagonal dies. The effects of the pre-stress ring on the dies were compared and analyzed and results show that using the angular split hexagonal die can extend the lifetime of forging dies.

• International Journal of Precision Engineering and Manufacturing
• /
• v.7 no.1
• /
• pp.3-8
• /
• 2006

This paper deals with an automated computer-aided process planning and die design system by which designer can determine operation sequences even if they have a little experience in process planning and die design for axisymmetric products. An attempt is made to link programs incorporating a number of expert design rules with the process variables obtained by commercial FEM softwares, DEFORM and ANSYS, to form a useful package. The system can provide a flexible process based on either the reduction in the number of forming sequences by combining the possible two processes in sequence, or the reduction of deviation of the distribution on the level of the required forming loads by controlling the forming ratios. Especially in die design module optimal design technique and horizontal split of die insert were investigated for determining appropriate dimensions of components of multi-former die set. Results obtained, using the modules, enable the design and manufacture of a die set for a multi-former to be more efficiently performed.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.9
• /
• pp.32-40
• /
• 2004

This paper deals with an automated computer-aided process planning and die design system by which designer can determine operation sequences even if they have a little experience in process planning and die design for axisymmetric products. An attempt is made to link programs incorporating a number of expert design rules with the process variables obtained by commercial FEM softwares, DEFORM and ANSYS, to form a useful package. The system is composed of four main modules. The process planning and the die design modules consider several factors, such as the complexities of preform geometry, punch and die profiles, specifications of available multi former, and the availability of standard parts. They can provide a flexible process based on either the reduction in the number of forming sequences by combining the possible two processes in sequence, or the reduction of deviation of the distribution on the level of the required forming loads by controlling the forming ratios. Especially in die design module an optimal design technique and horizontal split die were investigated for determining appropriate dimensions of components of multi-former die set. It is constructed that the proposed method can be beneficial for improving the tool life of die set at practice.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.32 no.3
• /
• pp.217-222
• /
• 2008

Equal channel angular pressing (ECAP) is one of the effective methods to produce bulk-nano materials by accumulating plastic strain into the workpiece without changing its cross-sectional shape in the multi-pass processing. However, the forming load becomes higher for manufacturing large specimens using conventional solid or split dies because of friction, flash formation, and usage of dummy specimen. In the present investigation, better split die was designed to reduce the forming loads and improve the geometrical accuracy of the specimen in the multi-pass ECAP. The new die exit channel was also designed to reduce the friction effect. Experiments with AA1050 specimens with a square cross-section were carried out to examine the design goal using the proposed split dies for routes A and C up to four passes. The numerical forming simulations were used to determine the effective geometry of various die models in the present work.

• Journal of Korea Foundry Society
• /
• v.28 no.4
• /
• pp.190-194
• /
• 2008

Thin-walled die casting of aluminum notebook computer housing with less than 1mm thickness was investigated by using computational solidification simulation and actual casting experiment. Three different types of gate design, finger, tangential and split type, were used and the results showed that sound thin-walled die casting was possible with tangential and split type gating design because those gates allowed aluminum melt flowed into the thin-wall cavity uniformly and split type gating system was preferable gating design than tangential type at the point of view of soundness of casting and distortion generated after solidification. Also, solidification simulation agreed well with the actual die-casting and the casting showed no casting defect and distortion.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.21 no.11
• /
• pp.1912-1920
• /
• 1997

In the analysis of metal forming process, ALE(Arbitrary Lagrangian Eulerian) finite element methods have been increasingly used for the capability to control mesh independently from material flow. The methods can be divided into two groups i.e., coupled and split formulations. In the present work, the split ALE formulation is used for computational efficiency. A split ALE finite element method developed for rigid-viscoplastic materials and applied to the analysis of hot square die extrusion. Since thermal state greatly affects the product quality, an ALE scheme for temperature analysis is also presented. As computational examples, profile shapes as square and cross-like sections are chosen.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.1307-1311
• /
• 2004

This paper deals with an automated computer-aided process planning and die design system by which designer can determine operation sequences even if they have a little experience in process planning and die design for axisymmetric products. An attempt is made to link programs incorporating a number of expert design rules with the process variables obtained by commercial FEM softwares, DEFORM and ANSYS, to form a useful package. They can provide a flexible process based on either the reduction in the number of forming sequences by combining the possible two processes in sequence, or the reduction of deviation of the distribution on the level of the required forming loads by controlling the forming ratios. Especially in die design module an optimal design technique and horizontal split die were investigated for determining appropriate dimensions of components of multi-former die set. It is constructed that the proposed method can be beneficial for improving the tool life of die set at practice.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.05a
• /
• pp.249-250
• /
• 2010

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

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