Development of concurrent stamping-piercing trimless hot stamping process

After a material undergoes hot stamping, post-processes are required to ensure that the final product has the expected quality. Typical post-processes are mechanical or laser trimming and piercing. These post-processes are expensive and time consuming because when the material undergoing hot stamping cools, its strength becomes very high. The purpose of this study was to develop a concurrent stamping–piercing trimless hot stamping process in which the hot stamping and hot piercing processes could be carried out in one operation for manufacturing automotive side sills. To achieve this purpose, first, a trimless blank was designed by carrying out an integrated numerical analysis including computational fluid dynamics and finite element analyses and employing an optimization technique. The process conditions for the hot piercing process were set based on the results of the finite element analysis of hot piercing process. Finally, the effectiveness of the developed hot stamping process was validated by performing a hot stamping experiment.