• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.6
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• pp.1077-1084
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• 2002

Optimum tool design is carried out fur a multi-stage rectangular cup deep-drawing and ironing process with the large aspect ratio. Finite element simulation is carried out to investigate deformation mechanisms with the initial design made by an expert. The analysis considers the deep drawing process with ironing for the thickness control in the cup wall. The analysis reveals that the difference of the drawing ratio within the cross section and the irregular contact condition produce non-uniform metal flow to cause wrinkling and severe extension. For remedy, the modification guideline is proposed in the design of the tool and the process. Analysis results confirm that the modified tool design not only improves the quality of a deep-drawn product but also reduces the possibility of failure. The numerical result shows fair coincidence with the experimental one. After tryouts of the tool shape, the rectangular cup has been produced in the transfer press.

• Transactions of Materials Processing
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• v.24 no.2
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• pp.115-120
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• 2015

Deep drawing of cylindrical cups is one of the most fundamental and important processes in sheet metal forming. Circular cups are widely used in industrial fields such as automobile and electronic appliances. Some of these cups are formed by a one-stage process, others such as battery cases and beverage cans are made by a multi-stage process. In the current study the multi-stage deep drawing of aluminum sheet metal is examined. The process consists of two deep drawing operations followed by two ironing operations. The press die, which can be used for the four-stage forming process, was manufactured allowing punch and die components to be easily changed for various experiments. The rolling direction of both the sheet and the drawn cups was always positioned toward the horizontal x-direction on the die face to minimize experimental errors during the progressive forming. The dimensional accuracy of the cylindrical cups formed at each stage and the earing defect due to the anisotropy of sheet were investigated. The influence of anisotropy on the thickness distribution was also examined. Both the thickness and the outer diameter of the cups were measured and compared for each set of experimental conditions. It was found that the dimensional accuracy of cups rapidly improves by employing the ironing process and also by increasing the amount of ironing.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.85-88
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• 2001

Examination of the die design is carried out for a multi-stage rectangular cup drawing process with the large aspect ratio with the aid of the finite element analysis. The analysis considers the deep drawing process with the ironing process for the thickness control in the cup wall. Simulation is performed to investigate the deformation mechanism in the initial design and the modified design. The analysis clarifies that the irregular cross section and the irregular contact condition produces unfavorable deformation. The analysis results show that the modified design improves the quality of a deep-drawn product with the low possibility of failure. The analysis result also shows good agreement with the experimental one.

• Journal of the Korean Society of Clothing and Textiles
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• v.23 no.7
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• pp.987-997
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• 1999

The purpose of this study was finding out the appropriate cleaning method for buried fabrics from old tombs focusing on the conservation of textiles. Cleaning effects and physical properties change depending on cleaning method have been analysed, The following results were obtained from this study : 1. Wet cleaning showed better effect on the cleaning of fabrics compared to solvent cleaning which meant more water-soluble soils existed than oily soils. 2. All the cleaning methods used did not cause any distorsion or shrinkage to the fabrics because fabrics had been stabilized for a long time 3. Addition of detergent to cleaning system decreased the friction of fiber during cleaning rocess so that the damage of fabrics could be minimized., 4. Ironing is an undesirable process because heat remarkably weakened fibers.

• Transactions of Materials Processing
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• v.7 no.4
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• pp.393-399
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• 1998

For minimizing wall thickness thinning of circular shells, a new stamping technology, the deep draw-ing process combined with ironing is approached and investigated. The design requirements for the deep drawing shells are to keep the optimum wall thickness with max. 10 percent thickness thinning of the initial blank thickness, to make uniform thickness strain distribution for the wall of circular shell and to improve the shape accuracy for the roundness and concentricity. In order to check the validity and effectiveness of proposed work, a sample process design is applied to a circular shell needed for a 4multi-stepped deep drawing. Through experiments, the variations of the thickness strain distribution in each drawing process are observed. Also a series of experiments are performed to investigate optimum process variables such as the geometry of tooling, radius and drawing rate. In particular, the advantage of current approach with ironing is shown in contrast to the conventional deep drawing process. From the results of proposed method, the optimum value of process variables are obtained, which contribute more uniform thickness strain distribution and better quality in the drawn product.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.459-464
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• 2001

The main object of this study is to develop a reliable FEM simulation technique for the analysis of Steel D&I Can bodymaking process using ABAQUS software. The body making process includes drawing, redrawing, 3 step ironing, doming. The newly developed FEM code in this research is based on the previous research achievement of POSCO for the drawing, redrawing and ironing process. The analysis is performed using two dimensional axisymmetric elements to analyze the punch force, the height of can, the distribution of residual stress and strain. The effect of blank thickness, gap of ironing die is also analyzed.

• Fashion & Textile Research Journal
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• v.2 no.4
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• pp.331-338
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• 2000

To study on the actual condition of care label attached to clothing and consumers' perception, 250 summer clothes sold at department store-blouse, trousers, one-piece dress, knit cardigan and skirt-were investigated during July 2000. In addition, a questionnaire was administered to 192 women in Taegu during August. The fiber contents of surveyed clothes were polyester 100% & polyester blend (26%), rayon 100% & rayon blend (18%), cotton 100% & cotton blend (17%), wool 100% & wool blend (14%) and others. All clothes surveyed were attached care label and the signals showed on care labels were 4~6 kinds about cleaning, squeezing, drying, bleaching, and ironing methods. 92% of clothes had to be dry-cleaned and only 8% could be wet-cleaned. Considered the surveyed clothes were for summer which needs frequent washing and the clothing items, the number of clothes had to dry-cleaned were too many. The bleaching instructions were no chlorine bleach (74%), no bleaching (21%) and others. The ironing instructions were cool ironing ($80{\sim}120^{\circ}C$) with cover (24%) and warm ironing ($140{\sim}160^{\circ}C$) with cover (69%) primarily. The drying instructions was dry on a hanger in the shade (54%) and 38% had no signal or incorrect signal. The properties of summer clothes considered important by consumers were wrinkled hardly, hand-washable, machine-washable, needed no iron and etc. Actually most of summer clothes were hand or machine-washed. Also, the majority of respondents felt inconvenient to have to dry-clean summer clothes. More than 80% respondents looked over care label and fiber content label before buying clothes. However most of respondents did not followed that instructions exactly and thought care label instructions were not correct. Considered this results, the suppliers have to make efforts to attach correct and appropriate care label which furnish the correct information to consumers.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.6
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• pp.629-637
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• 2013

In this study, a theoretical analysis method was suggested for predicting forming loads of continuous deep drawing and ironing processes (D.D.I. processes) by considering back tension and continuity equation, and FEA for D.D.I. processes was performed. Dimensions of a punch and a mold on the basis of design rules for a CNG storage vessel were applied for the analysis. To verify the suggested theoretical analysis, the results of theoretical analysis were compared with both those of FEA and experiments of previous studies. As the result of analysis, the values and tendencies of the loads predicted by the theoretical analysis were in agreement with those of FEA and the experiments. So, it is considered that the analysis suggested has reliability for predicting the forming loads of the continuous processes(deep drawing+ironing(1)+ironing(2)).

• Transactions of Materials Processing
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• v.19 no.4
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• pp.253-262
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• 2010

For multi-stage deep drawing process including ironing operation and biaxial forming in this study, tool developments are achieved, and the developed tool sets are applied to experimental investigations. In process and tool designs, a contact condition between intermediate blank and lower die is considered as the sequential one. In this study, the material used is cold-rolled thin sheet (SPCE) with the initial thickness of 0.4mm. From the experimental approaches, several failures such as tearing, localized thickening and thinning, are observed. To solve these failures, the contact surface on the lower die is modified. As the experimental results by applying the modified lower die, it is investigated that the failures are not occurred, and the excessive deformation behavior due to the thinning and thickening effects are decreased. Furthermore, the thickness distributions on the major axis and the minor axis of each intermediate blank are investigated to be already satisfied the target (ironing) thickness, respectively. By this systematic approach, it is confirmed that the experimental results show good agreements with the designed and required configuration of each deformed and final products.

• The Korean Journal of Rheology
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• v.1 no.1
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• pp.36-45
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• 1989

아이어닝 공정은 제품의 치수정밀도가 정확하게 조절괴는 정밀 금속 성형공정이다. 아이어닝 공정은 대개 냉간상태에서 행하여지며 그리고 때로는 단공정 대신에 다단식이 적 용된다. 본연구의 목적은 강소성 유한 요소법으로 단공정과 다단식 아이어닝 공정을 해석하 여 아이어닝 공정에 대한 적절한 설계변수와 최적 설계조건을 찾는데 있다. 본 연구에서는 공정설계게 있어서 공정변수를 다이의 원추각과 단의 개수로 주었다. 본 해석에서는 단공정 아이어닝과 다단식 아이어닝 공정의 성형하중, 응력과 변형도 분포 그리고 격자 변형을 계 산하였다 그리고 이 값들에 대한 공정 변수의 영향을 검토한 결과 성형하중과 격자 변형에 있어서 계산 결과와 잘 일치하였다.