Research and application of secondary drawing technology for the waist line of automobile rear door skin

In order to solve the quality problem caused by the sharpening of the waist line, taking the rear door outer panel as the research object, the paper develops the simulation of the double drawing of the waist line and the optimization design of the stamping die structure were carried out. In the design stage, the product forming process is numerically simulated. Through optimizing the stamping process by optimizing the stamping direction and the double drawing of the waistline, the quality problems of the front end of the waistline cracking and wrinkling and the slip line were solved. In the structural design of the stamping die, the gap between the upper and lower surfaces of the die is stable by adding double guide, pad block and balance block, etc., and the quality problems such as slip line caused by insufficient precision of the tooling are avoided. Finally, the process plan was used for mold manufacturing, and simulation results were used to guide physical debugging, resulting in qualified parts without cracking, wrinkling, and waistline slip within the benchmark. Research has shown that the secondary stretching scheme of the rear door outer panel can achieve industrial application of sharp waistline on the rear door outer panel.