• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.70-76
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• 1999

Recently most of researches for deep drawing process using sheet metal have been performed on the formability of axisymmetric shape but there have not been any concrete reports on the formability of non-axisymmetric shape In addition the conventional shape radius of the punch and die has been determined by the trying-and-error using industrial experimence and post processing test and only approximate shape radius of the punch and die has been determined by the trying-and-error using industrial experience and post processing test and only approximate shape radius of the punch and die has been present So in this study the optimal shape radius of the punch and die in deep drawing process with biaxisymmetric blank shape would be proposed. Through the deep drawing experiment it is found that in order to obtain the optimal products especially shape radius of the punch and die in all processes is very important.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.34 no.2
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• pp.103-111
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• 2011

The reduction of setup time is very important in a lot production system. A punch press is a typical system of lot production. This paper describes a case study to reduce setup time of a punch press manufacturing system. Especially, this case study reduced the time of die exchange in the case that the standardization of die height is impossible realistically because of diversity on die height and heavy expenses. This study adopts a supplementary die and supplementary blocks to make the use of auto-clamping device possible. The paper also gives a sequencing algorithm to reduce the number of exchange of the supplementary die.

• Transactions of Materials Processing
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• v.10 no.3
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• pp.235-245
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• 2001

Deep drawing process, one of sheet metal forming methods, is very useful in the industrial field because of its efficiency The deep drawing is affected by many process variables, such as blank shapes, shape radii of the punch and die, formability of materials and so on. Especially, blank shape is very important formability factor. In this study, in order to investigate the effects of blank shape, we suggested three kinds of blank shapes and examined friction test about three conditions. We measured punch load distribution according to punch stroke under the conditions of each punch and die shape radii and observed punch load of elliptical cup forming.

• Archives of Reconstructive Microsurgery
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• v.19 no.1
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• pp.12-20
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• 2010

Purpose: Industrial punch accidents involving fingers cause segmental injuries to tendons and neurovascular bundles. Although multiple-level segmental amputations are not replanted to regain function, most patients with an amputated finger want to undergo replantation for cosmetic as much as functional reason. The authors describe four cases of digital amputation by an industrial punch that involved the reinstatement of the amputated finger involving a joint and neurovascular bundle. Amputated segments were replanted to restore amputated surfaces and distal segments. Methods: A single institution retrospective review was performed. Inclusion criteria of punch injuries requiring replantation were applied to patients of all demographic background. Injury extent (size, tissue involvement), operative intervention, pre- and postoperative hand function were recorded. Result: Four cases of amputations were treated at our institute from 2004 to 2008 from industrial punch machine injury. Average patient age was 32.5 years (25~39 years) and there were three males and one female. Sizes of amputated segments ranged from $1.0{\times}1.0{\times}1.2\;cm^3$ to $3{\times}1.5{\times}1.6\;cm^3$. Tenorrhaphy was conducted after fixing fractured bone of the amputated segments with K-wire. Proximal and distal arteries and veins were repaired using the through & through method. The average follow-up period was thirteen months (2~26 months), and all replanted cases survived. Osteomyelitis occurred in one case, skin grafting after debridement was performed in two cases. Because joints were damaged in all four cases, active ranges of motion were much limited. However, a secondary tendon graft enhanced digit function in two cases. The two-point discrimination test showed normal values for both static and dynamic tests for three cases and 9 mm and 15 mm by dynamic and static testing, respectively, in one case. Conclusion: Though amputations from industrial punch machines are technically challenging to replant, our experience has shown it to be a valid therapy. In cases involving punch machine injury, if an amputated segment is available, the authors recommend that replantation be considered for preservation of finger length, joint mobility, and overall functional recovery of the hand.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.04a
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• pp.92-95
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• 2000

In order to obtain the optimal products in deep drawing process elliptical deep drawing tests were carried out with several shape radii of the punch and die. As parameters on testing shape radii of the punch and die were selected, In addition the conventional shape radii have been determined by trial=and-error using industrial experience and post processing test and only approximate shape radii of the punch and die have been presented. The optimal shape radii of the punch and die in elliptical deep drawing process with biaxisymmetric blank shape are proposed. In this study we suggest the appropriate conditions to be applicable to the catual manufacturing processes through the experiment and finite element method.

• Transactions of Materials Processing
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• v.10 no.3
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• pp.185-192
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• 2001

In order to obtain the optimal products in deep drawing process, elliptical deep drawing tests were carried out with several shape radii of the punch and die. As parameters on testing, shape radii of the punch and die were selected. In addition, the conventional shape radii have been determined by trial-and-error using industrial experience and post processing test, and only approximate shape radii of the punch and die have been presented. The optimal shape radii of the punch and die in elliptical deep drawing process with biaxisymmetric blank shape are proposed. In this study, we suggest the appropriate conditions to be applicable to the actual manufacturing processes through the experiment and finite element method.

• Transactions of Materials Processing
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• v.9 no.2
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• pp.120-127
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• 2000

Recently, most of researches for sheet metal deep drawing process have been performed on the formability of axisymmetric shape, but there are not any concrete reports on the formability of non-axisymmetric shape. In addition, the conventional shape radius of the punch and die has been determined by trial-and-error using industrial experience and post processing test, and only approximate shape radius of the punch and die has been presented. In this study, the optimal shape radius of the punch and die in deep drawing process with biaxisymmetric blank shape is proposed. Through the deep drawing experiment, especially it is found that in order to obtain the optimal products, and improvement of formability can be researched by selection of such punch and die shape radius that gives an adequate thickness distribution in all processes.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.8
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• pp.93-98
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• 2022

Adiabatic blanking is a method to improve productivity through an autocatalytic cycle that occurs repeatedly through plastic deformation and thermal softening caused by impact energy. In this study, an axisymmetric analysis model comprising a punch, die, holder, and specimen was developed to confirm the temperature and deformation characteristics caused by an impact load. Through this, the impact energy, diameter of the punch, gap between the punch and die, and the effect of the fillet were analyzed. Because this process occurs in a very short time, adiabatic analysis can be performed using the explicit time-integration method. The analysis, confirmed that it is necessary to design a structure capable of increasing the local temperature and plastic deformation by controlling the impact energy, working area, gap, and the fillet.

• Transactions of Materials Processing
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• v.32 no.5
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• pp.247-254
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• 2023

This study conducted the wear tests on bending punches coated with PVD CrN and examined the surface quality of the product formed by each punch in the forming of uncoated TRIP1180 sheets. The study quantitatively estimated the surface quality of the product by measuring the roughness and imaging the product surface. The correlation between the punch wear depth and the product surface roughness was quantitatively analyzed. The results showed that before failure occurs, the product roughness was comparable with that of the as-received, and the product surface was smooth without scratches and defects. However, after failure, the punch wear is caused by fretting wear mechanism, and a punch whose coating is not completely peeled plows the product surface, resulting in severe scratches with grooves and ridges on the product surface. Severe wear on the punch surface caused by fretting wear can rapidly degrade the product surface quality as it is directly affected by the punch surface condition, and the product surface quality accurately reflects the punch wear condition.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4057-4064
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• 2014

In this paper, attempts were made to design a preform for a final punch inexpensively using the proposed approximate optimization method or metamodel-based simulation optimization. The design objective of this work is to achieve a uniform distribution of effective strains, the angle dimension of the preformed punch is chosen as a design variable, and maximum underfill ratio is used as a constraint. For this optimization, a computer simulation of a practical punch forging process is run using DEFORM software, in which a preformed punch(workpiece), a master punch(upper die), and a bottom die are dealt with. A validation method is introduced to determine if the simulation results match the actual forging process. In addition, this work presents the detailed design optimization procedure consisting of (i) generation of an initial metamodel, (ii) metamodel optimization, (iii) validation of metamodel-predicted optimum, and (iv) metamodel improvement.