• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1999.03b
• /
• pp.34-39
• /
• 1999

IN this study when drawing a square cup blank holder pressure necessary for flange wrinkling prevention was experimentally studied. The materials used in the experiment were SPCC and SUS304 and drawing ratio was 1.62∼2.0 Two case for lubrication condition were experimented. One was without lubricant and the other was with lubrication of high viscosity.

• Transactions of Materials Processing
• /
• v.9 no.4
• /
• pp.356-361
• /
• 2000

In this study, when a square cup is under drawing, blank holder pressure necessary for flange wrinkling prevention was experimentally studied. The materials used in the experiment were SPCC steel and SUS304 and the drawing ratio was 1.62∼2.0. Two cases for lubricantion condition were investigated. One was without lubricant and the other was with lubricant of high viscosity.

• Transactions of Materials Processing
• /
• v.10 no.2
• /
• pp.115-122
• /
• 2001

It is well known, for many years, that deep drawability can be improved by applying variable blank holding force. To apply variable blank holding force during cup drawing, we set up cushion pressure control system on the hydraulic press, and the pressure control system is often called NC(Numerically Controlled) cushion system. A cushion pressure control experiment was carried out using the NC cushion and it was shown that the proposed system produced good performance. The comparison of drawability of square cups with and without NC cushion showed that the drawability could be greatly improved when S-shaped pressure curve was applied. This paper includes design details of the NC cushion system and experimental analysis of drawability with NC cushion system.

• Journal of the Korean Society for Precision Engineering
• /
• v.5 no.3
• /
• pp.31-42
• /
• 1988

This paper describes a computer aided process planning system called "Deep-Drawing", "Deep-Drawing" is designed for the drawing sequence of cylindrical and rectangular cups with or without taper and flange. The computer program has written in BASIC language with personal computer. Design Rules for process planning are formulated from process limitation, plasticity theory and experimental results including the know-how of many manufacturing factories. "Deep-Drawing" Capabilities include the analysis of drawing sequence by the determination of optimal drawing ratio, the determination of intermediate shape, dimensions, punch and die radius etc., the calculation of drawing loads and blank holder force to perform each drawing step, and the graphic outputs for the operation sheet.tputs for the operation sheet.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2006.05a
• /
• pp.48-52
• /
• 2006

The drawability of AZ31B magnesium sheet is estimated at various temperatures (200, 250, 300, 350 and $400^{\circ}C$), and forming speed (20, 50, 100 mm/min), thickness (0.5, 0.8, 1.0, 1.4 mm). The deep drawing process of circular cup and square cup were used in forming experiments. Experimental and FEM analysis are performed to investigate drawability and affection of controlled blank holding force. Through the controlled blank holding force, drawability was improved. This result is verified by FEM analysis. Through the observation of microstructure, the main cause is investigated as a quantity of the dynamic recrystallization.

• Transactions of Materials Processing
• /
• v.7 no.6
• /
• pp.594-602
• /
• 1998

The design analysis of axisymmetric, multi-stage deep drawing dies was performed using the rigid-viscoplastic finite element formulation. In the formulation the axisymmetric CFS algorithm was employed. Hill's non-quadratic normal anisotropic yield criterion and isotropic hardening rule were considered. For trial initial displacements and tool contact points. the geometric force equilibrium method was adopted. In order to see the validity of the formulation, the multi-stage deep drawing processes of shell-cylinder front part of hydraulic booster were simulated. The simulation showed good agreements with measurments and PAM-STAMP results.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1995.03a
• /
• pp.170-177
• /
• 1995

The restraining characteristics for the single square drawbead are discussed. The drawbead restraining forces adn maximum strains by the various drawing angles are measured experimentally. During this procedure , the drawing angles are varied from 0$^{\circ}C$ to 60$^{\circ}C$. Also, the wide range of experimental data of the drawing forces and maximum strains for the various drawbead dimensions, dimensions, clearances and blank holding forces are preseted.

• Transactions of Materials Processing
• /
• v.19 no.3
• /
• pp.179-184
• /
• 2010

The present study is focused on the deep drawability and product qualities of ultra thin beryllium copper sheet metal. The goal of this research is to investigate the limit drawing ratio in deep drawing of ultra thin beryllium copper metal. For the experiment, beryllium copper(C1720, $50{\mu}m$ in thickness) is used. Tensile test are also carried out to find out the material properties. Deep drawing experiments are carried out in Universal Testing Machine(UTM) to obtain limit drawing ratio. Deep drawing tests are carried out for various specimen sizes. Teflon film is used as a lubricant and constant blank holding force is imposed. Sheet thickness and surface hardness are measured along radial direction after deep drawing. Thickness is measured using optical microscope. For beryllium copper(C1720), the maximum LDR of 2.4 is obtained when the die shoulder radius is 20 or 30 times of sheet thickness.

• Transactions of Materials Processing
• /
• v.11 no.8
• /
• pp.716-723
• /
• 2002

A systematic investigation for the process design in deep drawing is necessary to improve the quality of drawn cups. This study concentrates mainly on the influence of process desing scheme on the product qualities in cylindrical cup drawing. Three types of process design scheme were chosen in this study. Case 1 is to draw a finished cup of 50mm in diameter in one stage, Case 2 and Case 3 are redrawing the first drawn cups of 55, 65mm in diameter to the final size respectively. Through experiments the maximum drawing force in two-stage cup drawing can be reduced up to 24% as compared with that of one-stage cup drawing. In addition, Case 3 process results in better product qualities than the other two processes in terms of the distributions of thickness and hardness.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1992.03a
• /
• pp.71-82
• /
• 1992

The frictional characteristics of Zn-Ni coated steel sheets were investigated by draw bead test and strip draw test. In strip draw test, the frictional characteristics were evaluated by the drawing force ratio (Tc/Ts) for half coating-stripped specimens. It is clarified that the drawing force ratio obtained by strip draw test is a convenient parameter compared to coefficient of friction obtained by draw bead test to evaluate the frictional characteristics of Zn-Ni coated steel sheets.