• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.280-283
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• 1999

Square dies are widely used for hot extrusion processes with high production rate. However the design and manufacture of square dies mainly relies on experience of industrial engineers To overcome such difficulty this study develops a method of automatic generation of NC-codes for the manufacture of extrusion square dies. The result shows that the method can reduce the lead time for the design and manufacture of square dies as well as eliminating engineers ow experience.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.739-742
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• 2000

From the experimental study of W-EDM for alloyed steel, the characteristics such as Hand Drum Form and surface roughness have been observed and evaluated for various conditions. In square hole, the increase of If as to made condition the calculate high value of surface roughness. Also compare dimensionless square hole with circle hole' graph. In circle hole, if a value of surface roughness IP 6 in a side of circle it show a 0.4${\mu}{\textrm}{m}$ and in IP 8, 0.6${\mu}{\textrm}{m}$, in IP 10, 0.7${\mu}{\textrm}{m}$, in IP 12. 0.8${\mu}{\textrm}{m}$ higher than before. This figure show the surface roughness is higher than before, because a table move in either X-axis or Y-axis in square hole, on the contrary, in circle there table move in X-axis and Y-axis at the same time. hand drum form getting small when wire tension increase 1000gf to 1500gf, at the same working conditions. the smaller of off time, the mailer of hand drum form in same condition and same wire tension. but if you compare square hole with circle hole' graph hand drum form displayed in maintained term of working condision, on the contrary, in case of square hole variation of hand drum form is more increase than a grow of IP

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.567-572
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• 2000

From the experimental study of W-EDM for alloyed steel, the characteristics such as Hand Drum Form and surface roughness have been observed and evaluated for various conditions. In square hole, the increase of IP as to made condition, the calculate high value of surface roughness. Also compare dimensionless square hole with circle hole' graph, In circle hole, if a value of surface roughness IP 6 in a side of circle it show a 0.4${\mu}{\textrm}{m}$ and in IP 8, 0.6${\mu}{\textrm}{m}$, in IP 10, 0.7${\mu}{\textrm}{m}$, in IP 12, 0.8${\mu}{\textrm}{m}$ higher than before. This figure show the surface roughness is higher than before, because a table move in either X-axis or Y-axis in square hole, on the contrary, in circle there table move in X-axis and Y-axis at the same time. hand drum form getting small when wire tension increase 1000gf to 1500gf, at the same working conditions. The smaller of off time, the maller of hand drum form in same condition and same wire tension. but if you compare square hole with circle hole' graph, hand drum form displayed in maintained term of working condision, on the contrary, in case of square hole variation of hand drum form is more increase than a grow of IP

• Transactions of Materials Processing
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• v.7 no.1
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• pp.72-80
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• 1998

This study is concerned with the thermo-biscoplastic finite element analysis of hot tube extrusion through square dies with a mandrel. The problem is treated as a non-steady state and the ALE description is used due to abruptly turning flow at the die aperture. Since the contact heat transfer coefficient and the friction factor are required in the analysis experiments are also carried out to determine the values, In order to apply ceramics to an extrusion die the study is focussed on under-standing the characteristics of the process. The simulated results provide the useful informations such as metal flow temperature distribution stress state etc. The elastic analysis of the dies is carried out to obtain the stress state of the ceramic dies.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.05a
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• pp.83-88
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• 1999

This study presents development of an software for process and die design of hot extrusion through square dies. The design of extrusion dies is still an art rather than a science with increasing complexity of shape and thinness of section. Therefore, most of the die design is still dependent on personal judgement, intuition and experience. The objective of this study is to develop an software system which includes a design rule extracted from literatures and experts in the extrusion industry. The system also includes finite element simulation program. The developed system is effectively used to design extrusion processes and dies with lead time and trial extrusion.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.764-768
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• 2001

This study presents development of an software for process and die design of hot extrusion through square dies. The design of extrusion dies is still an art rather than a science with increasing complexity of shape and thinness of section. Therefore, most of the die design is still dependent on personal judgement, intuition and experience. The objective of this study is to develop an software system which includes a design rule extracted from literatures and experts in the extrusion industry. The system also includes finite element simulation program. The developed system is effectively used to design extrusion processes and dies with lead time and trial extrusion.

• Transactions of Materials Processing
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• v.5 no.2
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• pp.97-104
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• 1996

It is very important to obtain the knowledge of loads and flow patterns in most processes because these information are the fundamental data of die design and process design. The objective of present study is to investigate loads and metal flow patterns for various process conditions in flat die extrusion of square-bars from circular billets. For analyzing the metal flow patterns of the billets photo etching is used on sections of split specimen. From this method metal flow patterns are analyzed for various area reductions friction factors and punch stroke through the process from initial-stage to final-stage. Experiments are carried out with hard solder billets at room temperature.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.315-318
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• 1995

The optimum design problem of a coat-hanger die is solved by the inverse formulation. The flow in the die is analyzed using three-dimensional model. The new model for the manifold geometry is developed for the inverse formulation. The inverse problem for the optimum die geometry is formed as the optimization problem whose objective function is the linear combination of the square sum of pressure gradient deviation at die exit and the penalty function relating to the measure of non-smoothness of solution. From the several iterative solutions of the optimization problem, the optimum solution can be obtained automatically while producing the uniform flow rate distribution at die exit.

• Journal of Ocean Engineering and Technology
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• v.14 no.4
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• pp.86-91
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• 2000

Numerical simulation of sheet metal forming for panels as other components has wide acceptance in the automotive industry. Therefore this paper was focused in the drawability factors (which are friction coefficient , radius of die and punch ) on the square cup deep drawing by the explicit finite elements code $PAM-STAMP^{TM}$. The computed results are compared with the experimental results to show the validity of the analysis. In order to compare the simulation results with the experiment results and predict the effect of drawability factors, the relationships between punch load punch stroke, and the relationships between thickness strain and distance are used. According to this study, the results of simulation by using $PAM-STAMP^{TM}$ will give engineers good information to access the drawability of square drawing.

• The Korean Journal of Air & Space Law and Policy
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• v.19 no.2
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• pp.163-177
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• 2004

Wenn man das fahrl${\"{a}}$ssige Begehungsdelikt in Bezug auf ein Niveau eines Risiko der objektiv vorhandenen tatbestandlichen Erfolgsm${\"{o}}$glichkeit und auf die n${\"{o}}$tige Sorgfaltspflicht, die die T${\"{a}}$ter nimmt, um das solches Risiko abzuhalten, berucksichtigt, ergibt sich der spezielle Fall selten bei der Person, mit dem hoch-gefahrlichen Berufszweig besch${\"{a}}$ftigt ist, auf den die bestehende Allgemeine-Theorie ${\"{u}}$ber das gafahrl${\"{a}}$ssige Begehungsdelikt gleichm${\"{a}}$ssig unanwendbar ist. Bez${\"{u}}$glich des Piloten des Milit${\"{a}}$rflugzeug ergibt sich oftmals ein bestmmter Fall, die die KontroIIe des Risiko gesch${\"{a}}$ftlich uber sein eigenes pers${\"{o}}$nliches Ermessen geht, und er nimmt die Pflicht, die notwendige milit${\"{a}}$rische Zielsetzung zuerst vor allem zu ber${\"{u}}$cksichtigen, wenn auch technisch, klimatisch und umstandehalber ein normales Niveau von Risiko ${\"{u}}$bersteigt wird und zugleich ein bedenkliches hoches Risiko mit sich gebracht wird. Aus diesem Anla${\beta}$ kann man folgem, da${\beta}$ der Pilot des Milit${\"{a}}$rflugzeug ein besonderer Fall ist, auf den die Kriterien in Bezug auf das Gebiet der Regel ${\"{u}}$ber das fahrl${\"{a}}$ssige Begehungsdelikt gleichm${\"{a}}$ssig unanwendbar sind. Und weil die Vermehrung der Gefahr des Flugzeug sofort an die Vermehrung der Gefahr seines eigenen Leben angeschlossen wird und daher es eine M${\"{o}}$glichkeit gibt, da${\beta}$ der Pilot dem Resultat eines Gefahr zum ersten Opfer f${\"{a}}$llt, ist die Regelung in der Punkt der Generalpr${\"{a}}$vention gegen das fahrl${\"{a}}$ssige Begehungsdelikt sinnlos. Und auch muB die militarpolitische Punkt, die Piloten des Milit${\"{a}}$rflugzeug gem${\"{a}}$${\beta}$ dem notwendigen Ausma${\beta}$ auszubilden und das Ausma${\beta}$ zu behalten, aktuell berucksichtigt werden.