• Journal of the Korean Society for Precision Engineering
• /
• v.30 no.10
• /
• pp.1111-1117
• /
• 2013

In this paper, the shape accuracy of the stamped hat-type product is quantified and analyzed with ultra high strength steel (UHSS) sheets. The shape of the hat-type product is designed in order to simplify the geometry of the side sill and the stamping methodology is proposed in order to verify the effect of the stamping procedure on the springback amount. Experiments and finite element analyses are conducted with four kinds of the forming sequences. The springback amounts are measured and compared according to the forming procedure with the embossing shape. Experimental result in company with analysis one illustrate that the springback amount is reduced with embossing in the padding operation. They also fully demonstrates the proposed forming procedure and the analysis method can be effectively applied to the process design for producing parts with ultra high strength steel.

• Transactions of Materials Processing
• /
• v.25 no.1
• /
• pp.21-28
• /
• 2016

In the current study, reduction of springback is quantified and the reasons for the reduction are investigated. The testing involved a digital servo motion applied to a U-draw bending to produce a hat-type product from high strength steels such as DP780 and DP980. The change in springback is compared between the constant speed motion and three kinds of servocontrolled motions during forming experiments. In order to predict the springback for the servo-controlled tool motion, a finite element method was utilized for the springback analysis considering a kinematic hardening model for the steel. The comparison of springback between the analysis and the experiments shows that they have similar tendencies. Also, the analysis results indicate that the springback reduction is greatly influenced by a decrease in the friction coefficient, which originates from the contact and detach phenomena between the tooling and the blank during the up-and-down motion of the upper die following the servo-controlled motion.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.14 no.4
• /
• pp.118-125
• /
• 2015

The roll-forming process is a highly productive incremental forming process and is suitable for manufacturing thin, high-strength steel products. Recently, this process has been considered one of the most productive processes in manufacturing high-strength steel automotive structural parts. However, it is very difficult to develop the roll-forming process when the cross-sectional shape of the product changes in the longitudinal direction. In this study, a roll-forming process for manufacturing high-strength steel automotive parts with a linearly variable symmetric hat-type cross-section was developed. The forming rolls were designed by the 3D CAD system, CATIA. Additionally, the designed forming rolls were modified by the simulation through the 3D elastic-plastic finite element analysis software, MARC. The results of the finite element analysis show that the final roll-forming roll can successfully produce the desired high-strength steel automotive part with a variable cross-section.

• Journal of Korea Ship Safrty Technology Authority
• /
• s.23
• /
• pp.51-64
• /
• 2007

Main concern of this subject is "hat type of hull shape is most important for building aluminum fishing vessel and suitable for domestic fisherman." For the this subject, We research from traditional hull shape of fiberglass fishing vessel and supply to our domestic fisherman with 3D render images. Following the above job making with concept design and basic drawing for product model. And most important research job with technical of aluminum vessel and products system and standard of job description. We filled two category with design and products for our domestic fisherman.