Experimental study of high-strength low-alloy sheet metal components with holes on the bending surfaces

Bending is one of the processes frequently used in the manufacture of sheet metal components. Springback is an important issue in bending operations since it controls the final shape of the parts. Hence, exact estimation of its value is essential for die design operations. In industry, the springback is usually obtained from empirical equations or mostly from handbook tables. These equations or tables are mainly suitable for components that have no holes on the bending surfaces, and they cannot be used for parts with any holes on the bending surfaces. In the present work, the influence of holes and their sizes on the bending surfaces of the high-strength low-alloy (HSLA) sheet metal steel using V-shape dies is studied. Different die angles, die widths, and sheet metal thicknesses are used in the experiments. The results show that all these parameters have an effect on the springback and the bending force, but their effects are not similar. An equation is derived for determining the bending forces for parts with holes on the bending surfaces.