• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.03a
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• pp.45-52
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• 1998

This study is to investigate the effects of warm deep drawing with aluminum sheets of A1050-H16 and A5052-H32 for improving deep drawability. Experiments for procucing circular cups and square cups were carried out for various working conditions, such as forming temperature and blank shape. The limit drawing ratio(LDR) of 2.63 in warm deep drawing of circular cups in case of A5052-H32 sheet, whereas LDR of A1050-H16 is 2.25, could be obtained and the former was 8 times higher than the value at room temperature. The maximum relative drawing depth for square cups of A5052-H32 material was also about 2 times deeper than the depth drawn at room temperature. The effects of blank shape, and temperature on drawability of aluminum materials as well as thickness distribution of drawn cups were examined and discussed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.117-120
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• 2003

Warm deep drawing which is one of the new forming technologies to improve formability of sheet metal is applied to the cylindrical cup drawing of Mg-alloy sheet metal. In experiments the temperature of die and blank holder is varied from room temperature to $300^{\circ}C$, while the punch is cooled by circulation of coolant to increase the fracture strength of workpiece on the punch corner area. Test material chosen for experiments is AZ31 magnesium sheet metal. Teflon film as a lubricant is used on both sides of a workpiece. The limit drawing ratio as well as thickness distributions of drawn cups are investigated and validity of warm deep drawing process is also discussed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.378-382
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• 2008

Since the sheet metal forming of Mg alloy is perform at elevated temperature, the effect of strain rates related with the forming temperature and forming speed and R-value is very important factor for formability and forming limits and deep drawing. It is investigated that the effect of material properties such as various temperature, forming speed and strain rates on formability and R-value of Mg alloy sheet in round cup deep drawing. Therefore, the investigation for process variables is necessary to improve formability and forming limits and deep drawing. Also, the effects of strain rate and drawbility were studied by the experiment. The temperature, forming speed, and strain rates and R-value are investigated. Forming of Mg alloy takes consider into temperature, proper forming speed and strain-rate and R-value the formed parts were good without defects for forming limits and deep drawing.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.8
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• pp.21-29
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• 2003

This paper describes a research work on the development of computer-aided design system for deep drawing & ironing of a high pressure vessel. An approach to the system is based on the knowledge-based rules. Knowledge for the system is formulated from plasticity theories, handbook, experimental results and empirical knowledge of field experts. An attempt is made to link programs incorporating a number of expert design rules with the process variables obtained by commercial FEM software, DEFORM and ANSYS, to form a useful package. It is composed of five main modules, which are calculation of product thickness, input, production feasibility check, process planning, and autofrettage process modules and two submodules, which are folding check and process variable verification submodules. Programs for the system have been written in AutoLISP on the AutoCAD 2000 using personal computer. The developed system makes it possible to design and manufacture large high pressure vessel requiring D.D.I. process more efficiently.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.7
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• pp.865-873
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• 2013

The deep drawing and ironing (DDI) process involving the use of a high-capacity horizontal press is used for manufacturing acompressed natural gas (CNG) pressure vessel. However, some variables of the DDI process have been determined based on the experiences of workers, and the short die life needs to be improved for manufacturing the pressure vessel withhighquality and lowcost. In this study, process variables such as the draw ratio, distance between dies, radius of rounding of drawing die, and angle of ironing die are chosen to enhance the reliability and improve the die life based on previous studies and experiences. The draw ratio limits at which no tearing or wrinkling occurs are determined using FEA, and the distances between dies, radius of rounding of drawing die, and angle of ironing die are optimized by the DOE method. The results of the optimal process variables are compared with those of the existing DDI process for verifying their effectiveness.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.1
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• pp.73-83
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• 1994

Press formabilities of aluminum sheets for automobile body were investigated. Plane strain stretching test (called RIST-PSST), cupping test and U bending test were performed to assess the press formability of aluminum sheets respectively. The results showed that aluminum sheets are generally inferior to cold-rolled steel sheet of deep drawing quality (CSP3N) in press formability. The limiting punch height (LPH) and limiting plane strain (FLCo) of aluminum sheets are 50%-70% level compared to that of CSP3N. Moreover, the limiting drawing ratios(LDR) of aluminum sheets are ranged between 1.95 and 2.1. The poor press formability of aluminum sheets is responsible for low values of total elongation and plastic anisotropy parameter in tensile characteristic. The shape fixability of aluminum sheets evaluated in U bending test is very poor due to its low elastic modulus compared to CSP3N.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.1 s.173
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• pp.87-93
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• 2000

Warm, forming technique which is one of the new forming technologies to improve formability of sheet metal is applied to the cylindrical cup drawing of stainless-aluminum. clad sheets. In experiments the temperature of die and blank holder is varied from room temperature to 18$0^{\circ}C$, while the punch is cooled by circulation of coolant to increase the fracture strength of workpiece on the punch corner area. Test materials chosen for experiments are STS304-A1050-STS304, STS304-A1050-STS430 clad sheets and A1050-0 aluminum sheet. Teflon film as a lubricant is used on both sides of a workpiece. The limit drawing ratio as well as quality of drawn cups(distribution of thickness and hardness)are investigated and validity of warm drawing process is also discussed.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.24-24
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• 2003

최근 자동차 산업이 발달함에 따라 철강업계와 자동차 회사에서는 전에 많이 사용하던 내연 무도금강판 대신 부식에 저항력이 강한 도금강판을 사용한 이후로 냉연강판의 가공 시에 야기되지 않았던 많은 문제점들이 나타났다 자동차용 강판의 경우 판재의 체적에 비하여 금형과 판재의 접촉면적이 큰 프레스 공정에서는 판재의 표면에 작용하는 마찰력의 크기가 판재의 스탬핑 성형성에 큰 영향을 미친다. 이는 마찰특성이 비록 재료고유의 성형한계에서는 영향을 미치지 못하나 스탬핑 공정에 있어서 금형과의 접촉면에서 마찰력의 크기가 패널의 변형률분포를 변화시켜 스탬핑 성형성에 큰 영향을 주는 것이다. 따라서 본 연구는 자동차용 도금강판의 표면 거칠기에 따른 판재의 표면 마찰 특성 변화를 알아보았다. 소재의 기계적 특성 측정은 UTM을 사용하였고, 도금층은 XRD, SEM을 이용하여 상분석 하였으며, 표면 거칠기는 AFM(Atomic Force Microscope), SJ-400(Mitutoyo)을 사용하여 표면 거칠기를 측정하였다. 또 드로잉 하중을 비드부에서의 굽힘-굽힘 풀림 소성변형에 의한 변형력 성분과 마찰력 성분으로 분리하여 강판의 쿠롬 마찰계수를 DBS(Draw bead simulation)로 측정하였다.

• Cartoon and Animation Studies
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• s.33
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• pp.31-53
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• 2013

In the early twentieth century, history of animation began by modern artists, they produced various experimental images with the newly invented film and cameras. Artists in the field of movie, photography, paintings and others manipulated images in motion. But as some animated movies won industrial success and popularity, they became the trend but experimental style of early animation preserved by so-called non-mainstreamers or experimental animators, counteracting commercialism. Disney animation also followed the trend by applying realistic Hollywood film style, the worse critics placed a low value on the animation and it tarnished the image, although it was profitable investment from a business standpoint. To make images realistic, they opened a drawing class that animators developed skills to imitate motions and forms from subjects in real life. Also some techniques and gizmos were used to mimic and simulate three dimensional objects and spaces, multiplane camera and compositing 3D CG images with 2D drawings. Moreover, they brought animation stories from fairly tales or folk tales, and Walt's personal interest in live-action movies, they applied Hollywood-film-like narratives and realistic visual, and harsh criticism ensued. On the surface early disney animations' potential seems to be weakened, but in reality it still exists by simplifying and exaggerating forms and color as modern arts. Disney animation employs concepts of the modernism paintings such as simplified shapes and colors to a character design, when their characters are placed together in a scene, that visual elements cause mental reaction. This modification gives a new internal experience to audiences. As conceptual colors in abstract paintings make images appeared to be flat, coloring characters with no shading make them look flat and comparing to them, background images are also appeared to be flat. On top of that, multi-perspective at background images recalls modernist paintings. This essay goes in details with the animation pioneers' works and how Disney animation developed its techniques to emulate real life and analyses color schemes, forms, and spaces in Disney animation compared with modern artists' works, in that the visual language of Disney animation reminds of impression from abstract paintings in the beginning of the twentieth centuries.