• Transactions of Materials Processing
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• v.15 no.4 s.85
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• pp.304-310
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• 2006

Due to a recent growth of the area of MEMS and a trend moving toward smaller scale, a micro manufacturing that is usually related with lithography is now emerging. Differently from traditional manufacturing processes, the micro or miniature manufacturing usually requires expensive sophisticated equipments and its characteristics are of high cost and of low productivity. However, a miniature stamping, which makes small sized product with a thin metal usually in the range of meso-scale, can be realized in a low cost and in a high productivity with relatively inexpensive equipments. For a successful development of miniature stamping, lots of obstacles, including material properties related with formability, have to be overcome. Since the thin metal shows distinctive characteristics, e.g., size effect and statistically scattered material properties, the formability of miniature stamping is not good in general and the possible shape with the miniature stamping is limited relatively simple shapes. Since the optimal blank improves formability and the improved formability can make up for problems of material properties, the possibility of success can be increased. This study is carried out to show the possibility of miniature stamping and to verify the effect of optimal blank for the miniature stamping.

• Design & Manufacturing
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• v.14 no.2
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• pp.49-55
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• 2020

Recently, when a new component of construction equipment is designed, a stamping process capable of producing parts having high appearance quality and precision has been gaining attention. However, in general, as it is developed based on existing parts made by welding metal sheets and tubes, frequent to die modification occurs, which increases the time and cost of developing new parts. Thus, it is necessary to reduce the cost by shortening the die development period. In this study, a stamping process was designed for the urea tank cover, which is a part for excavators, to reduce the die development period through sheet metal forming analysis. The stamping process was designed by determining the blank holding force after selecting the initial blank shape and size. The round value at the corner was modified such that formability is ensured. After selecting process parameters, the thickness reduction rate and spring-back effect were reviewed.

• Transactions of Materials Processing
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• v.8 no.4
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• pp.356-363
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• 1999

This paper discusses some techniques for the determination of optimum blank size and pre-form design for multi-stepped deep drawing of oval shell. The deep drawing process of oval shape has been regarded as more difficult than that of cylindrical shell because of its complicated behavior of plastic deformation. But there is insufficient information in this area to carry out successful deep drawing work of irregular products such as oval, rectangular, and square shapes. In order to find the optimum conditions, the drawing apparatus for two kinds of pre-form design are built, a series of drawing experiments performed, and thickness stain distributions measured. From the results of thess suggested experiments, various optimum process variables are observed and discussed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.14 no.3
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• pp.277-286
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• 2001

Among the ULSAB methods for the lightweight automobile body, Tailor Welded Blank(TWB) is adopted and the design process is developed for the existing component. Topology optimization conducted to find the distribution of the variable thickness. The number of parts and the welding lines are determined from it. In the detail design, size optimization is carried out to find the optimum thickness of each part and then, the final parting lines are tuned by shape optimization. A commercial optimization software GENESIS is utilized for the optimization processes.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.66-70
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• 2008

In this study, the formability of AZ31B magnesium alloy sheets was investigated by the analytical and experimental approaches. Tensile tests and limit dome height tests were rallied out at several temperatures between $25^{\circ}C$ and $300^{\circ}C$ to obtain the mechanical properties and forming limit diagram (FLD). The FLD-based criterion considering the strain-path and the blank temperature was used to predict the forming limit in a deep-drawing process of cross-shaped cup by finite element analysis. This criterion proved to be very useful in determining the optimal process conditions such as blank shape, punch velocity, minimum comer radius, fillet size, and so on, through the comparison between FEA and experimental data. In particular, the temperature of each tool that provided the best formability of the blank was determined by coupled temperature-deformation analyses. A practical method that can greatly reduce the forming time by increasing the punch speed during the forming process was suggested.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.3
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• pp.64-73
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• 2005

This paper is concerned with the simulation-based parameter determination for the tool design in the stamping process of the complicated auto-body member. The CAE procedure of the stamping process is proposed so that troubles such as wrinkle, springback and excess metal be eliminated with changing parameters such as the blank size, the restraining force of the draw-bead and the embossing shape in the die face. The selected indicators of failure during forming are wrinkling. the amount of spring after unloading of the tool, the amount of excess metal developed .The proposed analysis scheme is applied to the tool and process parameter design for the front side member of a RV car. The simulation results show that the scheme can produce sound product from the viewpoint of thickness distribution, the contact condition between tools and the blank, the shape accuracy and so on.

• Transactions of Materials Processing
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• v.10 no.3
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• pp.193-199
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• 2001

Forming more than two parts of sheet metal in a single stamping operation lowers production costs, reduces weight, and heightens dimensional accuracy. The tailored blank (TB) is a laser-welded or mash-seam-welded sheet metal with different thicknesses, different strengths, or different coatings. Recently, automotive manufacturers have been interested in tailored blanks because of their desire to improve the rigidity, weight reduction, crash durability, and cost savings. Therefore the application to auto-bodies has increased. However, as tailored blanks do not behave like un-welded blanks in press forming operations, stamping engineers no longer rely on conventional forming techniques. Field try-outs are very important manufacturing processes for an economic die-making. In the field try-outs, the rounded geometries of tool and the drawbead shape and size in die face are generally modified when the forming defects can not be removed by the adjustment of forming process parameters. In this study, the field try-outs of tailored door inner panel are introduced and evaluated. The behaviours of laser tailored blank associated with different thickness combinations in the forming process of door inner panel are described focusing on terms of experimental investigations on the formability.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.3
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• pp.323-333
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• 2012

This study aimed at helping to raise the reputation of Tteokgalbi for tourists visiting Damyang by studying the plating of Tteokgalbi. For 15 representative restaurants selling Tteokgalbi, we investigated the balance, blank, and proportions through studying the shape, material, and size of the dishes, and the number, shape, and garnish of one serving size of Teokgalbi. The results of our study suggested that round dishes (7 restaurants) and elliptical dishes (6 restaurants) similar to the shape of Teokgalbi are mainly used. For 13 out of 15 restaurants, the dishes were mainly casting pans in order to serve Tteokgalbi warm. The diameters of round dishes were 230 mm (3 restaurants), 265 mm (2 restaurants), and 300 mm (2 restaurants), and the elliptical dishes mostly had widths of 150 mm and lengths of 240 mm. The color of the dishes was N2-N3, similar to black, and N1, black of pale colors, because the dishes were mainly casting pans. The number of Teokgalbi per serving size was 3 in 12 restaurants. whole sesame was used most (7 restaurants) as a garnish. The results suggested that the color of the dishes and garnish could not imbue much distinction in the color of Tteokgalbi. In other words, Tteokgalbi is now served without consideration of the color, shape, size, or material of Tteokgalbi. The size of Tteokgalbi should be decided with consideration for the size of the dish and the amount of one serving size, and it is necessary to keep studying the process of making and garnish of Tteokgalbi.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03a
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• pp.26-29
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• 1999

Process design for elliptically shaped deep drawing products is various according to size shape and specification of products. This study presents two approaches to design the preform that is a key process for elliptically shaped products, One of these is that cross-section of punch is circular. Another is that for the improvement of characteristics for final products the cross-section of the punch is similar to rectangular shape. After forming the preform process design of top-part drawing is the same. In the study blank shape and dimension are obtained by applying a numerical formula and surface area constancy.

• Korean Journal of Veterinary Research
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• v.32 no.2
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• pp.251-258
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• 1992

Liposomal cephalexin was used m the dry period treatment of bovine mastitis due to Staphylococcus aureus. Liposomes were prepared by stable plurilamellar vesicle(SPLV) process. The shape and size of SPLVs were examined by transmission electron microscopy. The entrapping efficiency and stability of SPLVs were determined by high performance liquid chromatography or liquid scintillation counting. The size of SPLVs ranged from 0.1 to $4.01{\mu}m$ in diameter, with an entrapping efficiency of cephalexin of 25.8 %. The formulation of liposomal cephalexin was used for treatment were SPLV-entrapped cephalexin and free cephalexin with total cephalexin concentration of 250mg per quarters. All quarters were infused intramammarily at the end of lactation period by liposomal cephalexin, free cephalexin, or blank liposome with free cephalexin. The number of quarters cured by liposomal cephalexin(14/15 quarters, 93 %) was significantly higher than that by free cephalexin(7/15 quarters, 46%). or by blank liposome with free cephalexin(8/15 quarters, 53 % ) (p<0.05).