• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2001.05a
• /
• pp.235-238
• /
• 2001

Milli-structure components are classified as a component group whose size is between macro and micro scales, that is, about less than 20mm and larger than 1mm. The forming of these components has a typical phenomenon of bulk deformation with thin sheets because of the forming size. In this study, milli-structure rectangular cup drawing is analyzed and measured using the finite element method and experiment. Generally, milli-structure containers or cases like cellular phone vibrator consist of rectangular-shaped drawing to save installation space. A systematic approach is established for the design and the experiment of the forming processes for rectangular milli-structure cases. To verify the simulation results, the experimental investigations were also carried out on a real industrial product. The numerical analysis by FEM shows good agreement with the experimental results in view of the deformation shape of the product.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1593-1596
• /
• 2003

Sheet metal forming process is a non-linearity problem which is affected by various process variables, such as geometric shape of punch and die, frictional characteristic, etc.. Therefore, the knowledge of the influence of the process variables is needed in the design of sheet metal working processes. In this paper, deep drawing tests for blank holding force, punch speed and lubrication between sheet material and tool were carried out to investigate the influence upon sheet formability. Experimental results were discussed about the defects on the deformation behaviors during the forming process.

• International Journal of Precision Engineering and Manufacturing
• /
• v.2 no.4
• /
• pp.40-46
• /
• 2001

Bulging is a forming method to shape die cavity by using hydraulic pressure in tube or vessel. Bulging machine and die were developed in order to produce vessel for keeping warm. Bulging machine is a double type with two horizontal cylinders for bulging of two pieces at the same time. The developed die system has one bulging die and two drawing dies for necking at both ends of the tube. The diameter of tube expands by hydraulic pressure in tube. At the same time, thrust at both ends of the tube pushes tube in the direction of expansion to obtain high expansion rate with no crack. In this study, the bulging properties were investigated to solve tube crack and necking in manufacturing vessel by combining bulging and drawing. As a result, high expanding rate of tube radius without crack, precision necking and high productivity were obtained.

• Proceedings of the KSME Conference
• /
• 2001.06a
• /
• pp.471-476
• /
• 2001

Milli-structure components ate classified as a component group whose size is between macro and micro scales, that is, about less than 20mm and larger than 1mm. The forming of these components has a typical phenomenon of bulk deformation with thin sheets because of the forming size. In this study, milli-structure rectangular cup drawing is analyzed and measured using the finite element method and experiment. Generally, milli-structure containers or cases like cellular phone vibrator consist of rectangular-shaped drawing to save installation space. A systematic approach is established for the design and the experiment of the forming processes for rectangular milli-structure cases. To verify the simulation results, the experimental investigations were also carried out on a real industrial product. The numerical analysis by FEM shows good agreement with the experimental results in view of the deformation shape of the product.

• Journal of the Korean Society for Precision Engineering
• /
• v.13 no.1
• /
• pp.29-37
• /
• 1996

In this study, PC controlled CNC automatic cutting system is developed. Technological introduction of the control process and the computer programming has made possible not only the automatic control for cutting processing unit but also the easy-to-use graphic software that enables the cutting process. This program involves shape part drawing and amendment, pattern reading and saving, reading Autocad file, nesting process, kerf compensation, automatic cutting path generation, NC file conversion and motor control. Software is devided into 3 modules for easy work. First step enables drawing, amendment and pattern making, followed by automatic nesting and cutting path generation with kerf compensation. In the final step, drawing data is transmitted for the resulting automatic cutting processes. This software would be applicated in gas cutting and textile cutting so that it improves the productivity of cutting process.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2001.05a
• /
• pp.28-31
• /
• 2001

Friction for sheet metal forming affects improvement of deep drawing formability. The deep drawing is affected by many process variables, such as lubricant, blank shapes, shape radius and so on. Especially, lubrication is very important formability factor. In this study, in order to investigate fraction coefficient of sheet metal forming, we examined friction test about three conditions, such as non-lubrication, full lubrication and film lubrication. We measured friction coefficient according to pin load under the conditions like deep drawing die. Mean friction coefficient for film lubrication condition would be very useful value to improve drawability.

• Journal of Fashion Business
• /
• v.15 no.1
• /
• pp.63-79
• /
• 2011

This study examines the relationship between breast shape and brassiere construction through the comparative analysis of brassiere pattern on the breast shape. This researcher drew the brassiere pattern of developing a pre-study for Chinese female adults according to average size based on the four breast shapes. And then we measures brassiere pattern size and comparatively analyzes breast between size and shape. Comparative analysis results of brassiere patterns are verified differences of size and shape on the breast shape. Above all an angle of cup dart showed remarkable differences on the breast shape. An angle of cup dart isn't proportioned to breast size. An angle of cup dart for cone shape is bigger than dome shape. Because cone shape breast is protruded center part but dome shape breast have a shape of smooth curve like a half globe. So an angle of a cone shape breast cup dart is determined bigger than dome shape breast. For increasing the uplift effect of brassiere, brassiere pattern is different on the breast shape. And a brassiere pattern need different drawing methods about the angle of cup dart, breast inner side diameter, slope and so on. This study has an important significance that it established a mechanical relationship of breast shape and brassiere pattern.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.177-180
• /
• 2005

Three dimensional shaded images are standard visualization method for CAD models on the computer screen. Therefore, much of the effort in the visualization of CAD models has been focused on how conveniently and realistically CAD models can be displayed on the screen. However, shaded 3D CAD data images captured from the screen may not be suitable for some application areas. Technical document, either in the paper or electronic form, can more clearly describe the shape and annotate parts of the model by using projected 2D line drawing format viewed from a user defined view direction. This paper describes an efficient method for generating such a 2D line drawing data in the vector format. The algorithm is composed of silhouette line detection, hidden line removal and cleaning processes.

• Journal of computational fluids engineering
• /
• v.16 no.1
• /
• pp.22-29
• /
• 2011

In this study, the glass fiber drawing from a silica preform in the furnace for the optical fiber manufacturing process is numerically simulated by considering the radiative heating of cylindrically shaped preform. The one-dimensional governing equations of the mass, momentum, and energy conservation for the heated and softened preform are solved as a set of the boundary value problems along with the radiative transfer approximation between the muffle tube and the deformed preform shape, while the furnace heating is modeled by prescribing the temperature distribution of muffle tube. The temperature-dependent viscosity of silica plays an important role in formation of preform neck-down profile when the glass fiber is drawn at high speed. The calculated neck-down profile of preform and the draw tension are found to be reasonable and comparable to the actual results observed in the optical fiber industry. This paper also presents the effects of key operating parameters such as the muffle tube temperature distribution and the fiber drawing speed on the preform neck-down profile and the draw tension. Draw tension varies drastically even with the small change of furnace heating conditions such as maximum heating temperature and heating width, and the fine adjustment of furnace heating is required in order to maintain the appropriate draw tension of 100~200 g.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.16 no.2
• /
• pp.248-258
• /
• 1992

Three-dimensional rigid-plastic finite element formulation based on the membrane theory was described and a computer program for large deformation analysis was developed. In the formulation, normal and planar anisotropy of sheet material and rotation of the principal axes of anisotropy was taken into consideration. Sheet metal was assumed to be rigid-plastic material obeying Hill's quadratic yield criterion and its associated flow rule. Deep drawing process, as a preliminary test, for normal anisotropic material was analyzed in order to examine the validity of developed finite element program. The results were consistent with the existing finite element solutions or experimental data. The present study was mainly concerned with the influence of planar anisotropy on deformation behaviour. Finite element analysis and experiment were carried out for the whole process of deep drawing of planar anisotropic material. The computational and experimental results on the shape of ear, strain distribution and punch load were in good agreement.