3.06 - Multipoint Forming

Abstract

The double curved sheet-metal parts with large size and thin-walled have been used in the field of aviation, spaceflight, shipping, vehicle, and architecture widely. Generally, the double curved sheet-metal parts are formed by solid die, but the cost for manufacturing of solid die is very high and the manufacturing cycle of solid die is very long. In order to solve the problems of solid die, Jilin University have done lots of works about flexible sheet-metal forming technology and digital manufacturing, such as multipoint forming (MPF) and flexible stretching forming (FSF). MPF is using a group of punch elements to shape the surface of the tool in place of a solid die firstly. Then, each element can be controlled by computer so that the curved tool surface can be changed at any time. MPF have been used for the manufacture of steel structure of Bird's Nest Stadium (Beijing Olympic Game). FSF can increase the rate of materials utilization and close-fitting dies sharply than conventional stretch forming, by replace integrally gripping jaws to discrete multi-gripping jaws. Flexible control of multi-gripping jaws also can be achieved in a simple way based on new principle of stretching forming. FSF have been used in the cab of high-speed train and landmark building successfully. Furthermore, flexible roll forming, spin forming, continuous rolling, and stamping with flexible bank-drawer also pioneered at Jilin University, based on lots of numerical simulation and experiments.