• International Journal of Precision Engineering and Manufacturing
• /
• v.3 no.4
• /
• pp.37-42
• /
• 2002

The purpose of this paper is comparing the forging effect according to the shape of preforms of cup shaped powder forging product, and extending the application of powder forging technology to more complicated cup-shaped products like pistons. In order to achieve this, preforms are provided by compacting, sintering, and machining to 5 different shapes, then forged to the final shape of products. The workability for sintered aluminium powder material was examined and confirmed its slope was 0.5 as known. Density and strain loci of forged products are also evaluated and compared. On the basis of the results, the most effective shape of preform was proposed. The preform for the piston which is 50mm in diameter was prepared and hot forged successfully to the final product.

• Transactions of Materials Processing
• /
• v.10 no.1
• /
• pp.15-22
• /
• 2001

The sensitivity method has been utilized to find initial blank shapes which transform into desired shapes after forming. From the information of die shapes, target shape and material properties, the corresponding initial blank which gives final shape after deformation has been found. Drawings of a trapezoidal cup, a cross-shaped cup and an oil pan have been chosen as the examples. At every case the optimal blank shape has been obtained only a few times of modification without any predetermined deformation path. With the predicted optimal blank, both computer simulation and experiment are performed. Excellent agreements are recognized between simulation and experiment at every cases Through the investigation, the sensitivity method is found to be effective in obtaining optimal blank shapes in drawing of complex shapes.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.9 s.174
• /
• pp.27-33
• /
• 2005

This study deals with the truing of diamond wheel fur the manufacture of micro v-shaped grooves with fine sharp edges in the grinding. Fine micro v-shaped grooves are key components to fabricate LGP(light guide plate), optical fiber connector and so on. Conventional v-shaped groove methods such as etching and lithography are difficult to make grooves with accuracy and cutting by lathe is difficult to select target materials. Therefore, as a preliminary stage to developing the grinding technology that will be expected fabrications for micro 3-dimensional structure of high effectivity and accuracy and freed up the restrictions of machinability to the materials for micro v-shaped grooves, truing is carried out with resin bond diamond wheel and electroforming diamond wheel using a cup-type truer. From the experimental results, it is found that the effects according to working direction of the cup-type truer and the restrainable methods of plastic deformation that is generated at wheel edge are examined. As a result, fine micro v-shaped diamond wheel was obtained, which are applicable to micro grinding for optical devices.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.11
• /
• pp.63-68
• /
• 2000

The purpose of this paper is to compare the forging effects according th the shape of preforms of cup shaped powder forging product, and extend the application of powder forging technology to more complicated cup-shaped products like pistons. In order to this, preforms are provided by compacting, sintering, and machining in various shapes, then forged to final shape of products. The workability for sintered aluminium powder material is examined. Density and strain loci of forged products are compared, and the most effective shape of preform is proposed. The preform for a piston of 50mm in diameter is provided and hot forged to final product.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.24 no.1 s.173
• /
• pp.79-86
• /
• 2000

In this study, a method of optimal blank design using the sensitivity analysis has been proposed. To get sensitivity a well-known commercial code PAM-STAMP has been used. In order to verify this method, formings of square cup, clover shaped cup and L shaped cup have been chosen as the examples. With the predicted optimal blank both computer simulation and experiment are performed. Excellent agreements are recognized between the numerical results and the target contour shapes. Through the investigation, the proposed systematic method of optimal blank design is found to be effective in the design of the deep drawing process.

• Journal of Fashion Business
• /
• v.12 no.6
• /
• pp.81-92
• /
• 2008

The purpose of this study is to develop the applied brassiere pattern of women which are fitting for 75A. The constructing of this experimental brassiere were lower cup, upper cup, front panel and U-wing as well as a full cup embcing the entire breasts. Basing on the bra model from domestic experiment results, development of an applied design, round side type pattern, has been suggested. Thus, suggesting the round variation design bra, which is an applied design based on the basic model based on the breast volume. Based on the sizes that are in reference to Size Korea (2004) and related previous researches, the basic model that has been experimented with 11.4% polyurethane and 88.6% Nylon as the materials, has been selected as the model of research. This takes 75A, the size of which is set according to the underbust circumference and the breasts circumference, as the basic model. It is an application in terms of design, and there is no change to the cup volume or size because it has been moved only from the cutting line. The applied design changes the right side of the lower cup into an easily-movable form and attaches it to the upper cup, and the lower cup takes the right part of the upper cup to form a cup shape of round variation design. It also changes basic straight form of the wings, and alters them into U-shape.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.38 no.6
• /
• pp.887-895
• /
• 2014

The study provides baseline data on developing ready-to-wear clothes for adult females in their twenties who have finished shaping their bodies and have realized an ideal shape. We analyzed the data from females aged from 20 to 29 in "The $5^{th}$ Size Korea Survey" and "The $6^{th}$ Size Korea Survey", and sorted body shapes into several types according to drop values before analyzing and comparing the characteristics among groups. We also referred to the change by year in the size of upper inner wear. To classify body shapes, three drop values were assigned for bust girth - waist girth, hip girth - waist girth, hip girth - bust girth; through cluster analysis all data were classified into three body types. Type 1 is more like normal body shapes with small drop values at the bust girth - waist girth and well-build lower body. Type 2 is X-shaped body shaped like a fiddle with big drop values at all parts. Type 3 is Y-shaped body with a big drop value at the bust girth - waist girth and well-build upper body. Type 2, X-shaped body, has the majority of distribution in every year, which proved to be the most idealistic body shape. There was a change in the brassiere cup size. Korean ladies in their twenties have larger breasts. The body shapes of Korean females in their twenties are increasingly like those of westerners. Bust girth is a very critical element to set measurements and design patterns for upper wear; consequently, a change in the size of breasts should be considered.

• Horticultural Science & Technology
• /
• v.35 no.2
• /
• pp.265-275
• /
• 2017

Selection of double-flowered plants at the seedling stage is one of the main purposes of stock breeding programs. Eight stock cultivars of Matthiola incana L. named 'Nobel', 'Cinderella', 'Pacific', 'Avalanche', 'Midblue', 'Lavender', 'Goddess' and 'Esfahan', with different percentage of double-flowered plants were used for examining the relationship with three morphological types of cotyledons. The results of a chi-square test indicated that in heart-shaped (HC) and cup-shaped cotyledon (CC) populations, the number of plants with double flowers was much more than that of single flowers and CC seedlings rarely produced single flowers. Therefore, increasing the number of CC seedlings can improve the percentage of double flowers. The highest and lowest numbers of CC seedling were observed in high double and single flower cultivars, respectively. Single flower cultivars showed the maximum count of dumbbell-shaped cotyledons. Chromosome pairing of these cultivars was evaluated using the squash technique. Aneuploid cells were found in 'Nobel' and 'Goddess' cultivars, which showed the highest percentage of CC seedling. Based on morphological measurements, the highest value of inflorescence size was observed in the seedlings with cup-shaped cotyledons.

• Transactions of Materials Processing
• /
• v.6 no.5
• /
• pp.416-424
• /
• 1997

In the present study, a contact search and check algorithm for general tool surface described by triangular FE patch is proposed. To improve numerical stability, SEAM element using the linear Coons interpolation has been used. To check the proposed algorithm, both clover cup and L-shape cup deep drawing processes are calculated. The computed results shows that the proposed contact algorithm can be successfully applied for sheet metal forming processes with general shaped tools.

• Journal of the Korean Society for Precision Engineering
• /
• v.10 no.3
• /
• pp.198-204
• /
• 1993

The study is concerned with finite element analysis and design of axisymmetric deep drawing by local heating. When the bottom shape of a cup is not flat but in complex-shaped, i.e., hemispherical, the cup cannot be drawn in one or two processes in the conventional deep drawing process and the limit drawing ratio is limited as well. By introducing local heating selectively with regards to the heating position, the formability of the sheet metal can be greatly increased with the reduced number of processes. In the Process analysisthe rigid- viscoplastic finite element method is employed and the temperature effect is incorporated. Bishop's step-wise decoupled method is employed to analyze the thermomechanical interaction between deformation and heat transfer. Axisymmetric deep drawing of a hemisphere-bottomed cup has been analyzed for various combinations of heat application in the punch and the die. At the first stage of deep drawing stretch forming is practically carried out by firmly pressing the blankholder with the punch and the die heated at various levels of temperature. Then at the second stage the same cup is drawn for the saame or different combination of temperature. From the computation, it has thus been shown that the fromability of a cup is greatly increased in two-stage deep drawing with increased limet drawing ratio.