• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.03a
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• pp.136-139
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• 1997

Applications of commercial software DEFORM-3DTM for 3-D simulation in extrusion process are developed for the analysis of twisting of extruded products. Because the elliptical shape has at least one line symmetry, the twisting is not occured during the extrusion. But, the results of extrusion simulation of the elliptical shape show that the twisted boundary of the die surface makes the material inside die surface rotate with the constant angular velocity. Otherwise, the simulation results of the S shaped product show that the twisting can be occured by the only 180$^{\circ}$rotation symmetry of S shape without no line symmetry and show that the angular velocity increases by the only 180$^{\circ}$rotation symmetry without no twisted die surface between on the die entrance section and on the die exit section. The results of the analysis show that the angular velocity of the extruded product changes with die length and friction condition.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.473-477
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• 2000

The experimental study of die-sinking electrical discharge machining(EDM) was conducted for Cold Die Alloy Steel of SKD-11 with rotary electrode according to the peak current of 11A, 15A and 19A, and the duty factor of 0.24, 0.45. dielectric fluid flow through the electrode inside according to the change of electrode internal diameter during the EDM working. Material removal rate(MRR) was increased with flushing & rotation of electrode at the condition for the peak current of 15A, 19a but the MRR is decreased at the flushing only. The more surface roughness was obtained for the case of the flushing & rotation under the peak current of 19A.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.06b
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• pp.54-59
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• 1998

In this study, two kinds of life prediction method for hot forming die are developed . One is empirical method requiring some experiment that evaluate thermal softening of die material accoring to operating conditions. The other is analyticl method that calcuate wear quantity of die occuring during the forming process. Wear is a predominant factor as well as plastic deformation and heat checking . And, these methods are applied to prodict tool life real die producting part for automobile. Thus , the applicability and the accuracy of the presented methods are investigated. Using the verified life prediction method above , optimal blocker die design minimizing the finisher die is done.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.1
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• pp.167-174
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• 2012

For high production rate of parts requiring multiple operations such as punching, blanking, or other operations are generally done with progressive dies. However, progressive die is generally limited to use for sheet metal forming due to the technical difficulties in rod or bulk material. This study proposes a new technique of progressive die and forming process for asymmetric automotive door striker, which is conventionally manufactured with separate tandem processes using solid rod. In order to design forming process and die, FEM simulation was performed to divide proper intermediate processes and analyze its formability. As a result, Forming processes were divided into 3 stages with upper and side punches and also, workpiece feeding and location mechanism was designed and manufactured in this study. Finally, forming tryouts were carried out by using the manufactured progressive die to verify the forming quality and productivity.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.195-196
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• 2006

In recent years, demands for sintered ferrous material with higher strength are increasing. To satisfy these demands, studies and commercial use of the die wall lubrication method, the warm compaction method and the combination of both methods are widely carried out to achieve high density. The die wall lubrication warm compaction method makes it possible to achieve high density by reducing internal lubricant through die wall lubrication, although the method involves several issues such as prolonged cycle time due to lubricant spraying and difficulty in spraying lubricant in the case of compacting with complicated geometry. Meanwhile, the conventional warm compaction method requiring no die wall lubricant application cannot achieve such a high density as in the case of die wall lubrication warm compaction due to higher volume of internal lubricant. However, this report discloses our study result in which the possibility of improving density is exhibited by using a lubricant type with superior dynamic ejection property that can reduce volume of lubricant additive.

• Transactions of Materials Processing
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• v.30 no.4
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• pp.172-178
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• 2021

The cold forging process induces material deformation in an enclosed space, generating a very high forging load. Therefore, it is mainly designed as a multi-stage process, and fatigue failure occurs in forging die due to cyclic load. Studies have been conducted previously to quantitatively predict the fatigue limit of cold forging dies, however, there was a limit to field application due to the large error range and the need for expert intervention. To solve this problem, we conducted a study on the introduction of a real-time forging load measurement technology and an automated system for quantitative prediction of die life cycle. As a result, it was possible to reduce the error range of the quantitative prediction of die life cycle to within ±7%, and it became possible to use the die life cycle calculation algorithm into an automated system.

• Agricultural and Biosystems Engineering
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• v.6 no.1
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• pp.27-33
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• 2005

Soy protein meat analog was produced using a twin-screw extruder attached with a cooling die. Heat transfer analysis was performed for cooling dies with various die sizes at the four different moisture contents of feed during extrusion process. The experimental design consisted of two cooling die widths (30 and 60 mm), three cooling die lengths (100, 200, and 300 mm), four product moisture contents (71.2, 67.0, 61.6 and 55.8%), and water and water plus ethylene glycol as cooling material. When water was used as cooling medium, the values of equivalent overall heat transfer coefficient $(U_e)$ for each die width of 30 and 60 mm were in the range of 187.0 - 341.4 and $358.5-191.6W/m^2^{\circ}C$ depending on the size of die length. Convective heat transfer coefficients between cooling water and inside die wall of cooling channel $(h_c)$ for both die widths of 30 and 60 mm were 588.5, 416.1, and $339.8W/m^2^{\circ}C$ for each die length of 100, 200, and 300 mm. Convective heat transfer coefficients between product and inside die wall of product channel $(h_p)$ for each die width of 30 and 60 mm were in the range of $434.6-888.1W/m^2^{\circ}C$ and $460.7-1014.5W/m^2^{\circ}C$ depending on the size of die length. When water plus ethylene glycol was used as cooling medium, the values of $U_e$ were in the range of $143.9-319.6W/m^2^{\circ}C$ and $177.8-332.7W/m^2^{\circ}C$ for each die width of 30 and 60 mm depending on the size of die length.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.3
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• pp.75-80
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• 2008

The progressive die performs a work of sheet metal processes with a piercing, notching, embossing, bending, drawing, cut-off etc. in many kinds of pressing. Now a days, these processes have been evaluated as a advanced tooling method to increase the productivity and high quality assurance. The first step analyzing of die design is production part review, then the arrangement drawing of product design and strip process layout design should be done as a next steps with a FEM simulation for its problem solution. After upper procedure were peformed, it was started to make the die, then tryout and its revision of the die and product quality, safety, productivity etc. were done continually. For the all of these process, we mobilized the theory and practice of sheet metal forming, die structure, the function and activity of die components, and the others of die machining, die material, heat treatment and know‐how so on. In this study the features of representative are production part analyzing through the FEM simulation of bending area with a considering spring back problem by DEFORM.

• International Journal of Precision Engineering and Manufacturing
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• v.2 no.2
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• pp.38-47
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• 2001

This paper decribes the development of computer-aided design of a very precise progressice die for lead frame of semiconductor chip. The approach to the system is based on knowledgr-based rules. Knowledge of fie이 experts. This system has been written in AutoLISP using AutoCAD ona personal computer and the I-DEAS drafting programming Language on the I-DEAS mater series drafting with on HP9000/715(64) workstation. Data exchange between AutoCAD and I-DEAS master series drafting is accomplished using DXF(drawing exchange format) and IGES(initial graphics exchange specification) files. This system is composed of six main modules, which are input and shape treatment, production feasibility check, strip layout, data conversion, die layout, and post processing modules. Based on Knowledge-based rules, the system considers several factors, such as V-notches, dimple, pad chamfer, spank, cavity punch, camber, coined area, cross bow, material and thickness of product, complexities of blank geometry and punch profiles, specifications of available presses, and the availability of standard parts. As forming processes and the die design system using 2D geometry recognition are integrated with the technology of process planning, die design, and CAE analysis, the standardization of die part for lead frames requiting a high precision process is possible. The die layout drawing generated by the die layout module s displayed in graphic form. The developed system makes it possible to design and manufacture lead frame of a semiconductor more efficiently.

• Koreanishche Zeitschrift fur Deutsche Sprachwissenschaft
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• v.1
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• pp.349-374
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• 1999

In der vorliegenden Arbeit wird versucht, die Verhaltnisse yon Informationsstrukturierung (information packaging) und Scrambling am Material des Deutschen zu untersuchen. Bei der Informationsstrukturierung geht es um die Ordnung der Elemente des Satzes, die durch die Kommunikationssituation, die Intentionen des Sprechers sowie seine Kenntnisse und Annahmen tiber $Wissensvorr\"{a}te\;des\;H\"{o}rers$ determiniert wird. Deutsch ist eine Sprache mit 'freier' Abfolge der Satzglieder. Die Grammatik des Deutschen erlaubt $S\"{a}tze$, die dasselbe bedeuten und sich in ihrer Konstituentenfolge unterscheiden. Diese variable Wortfolge (Topikalisierung und Scrambling) und der Satzakzent im Deutschen wirken systematisch mit der Informationsstruktur (Topik­Pradikation-Struktur und Fokus-Hintergrund-Struktur) zusammen. Es ist allgemein bekannt, $da\ss$ Scrambling und Topikalisierung sowohl diskurssemantische als auch informationsstrukturelle Effekte $ausl\"{o}sen$. In der vorliegenden Arbeit wird zuerst auf problematische Aspekte der $Ans\"{a}tze$ hingewiesen, die Scrambling mit (diskurs-)semantischen Begriffen wie 'Definitheit', $'Spezifit\"{a}t'\;oder\;'Familiarit\"{a}t'$ sowie mit der traditionellen 'Thema-Rhema-Gliederung' zu erklaren versuchen. Dann wird Scrambling unter Bezug auf den Zusammenhang zwischen Fokus-Hintergrund-Struktur und grammatischer Struktur behandelt. Dabei wird festgestellt, dass Satzakzent und Scrambling systematisch mit der Fokus-Hintergrund-Gliederung des Informationsbereiches im Satz interagieren und dass die $Umstellungsm\"{o}glichkeiten$ im Mittelfeld zur $\"{A}nderung$ der Fokusprojektion, d.h. zur Umordnung von Hintergrund-Teil und Fokus-Teil $f\"{u}hren$. Scrambling kann dazu im Zusammenwirken mit dem Satzakzent und einem bestimmten Intonationsmuster einen 'Kontrasttopik' - Effekt $ausl\"{o}sen$.