Research on the relationship between the number of rotary draw bendings and the shape precision of a bent hat-section profile

Curvature spring-back and section distortion are the primary quality defects of bent sections. Experiments on LY12M hat-section profiles have been made using a rotary draw bending machine, with the aim of determining the influence of the number of rotary draw bending cycles on curvature spring-back and section distortion. In order to enhance the part quality and improve the production efficiency, the authors demonstrate the method of imposing a stretching force and a mold-repair angle, thus, reducing the number of rotary draw bending cycles. By means of experiment on a rotary draw bending machine with a stretching force, the best side pressure, stretching force and appropriate mold-repair angle are determined, which reduces the number of required rotary draw bending cycles to 2. Satisfactory parts have been made by this technique.