Effect of Die Shoulder Radius on Material Surface Scratch in V-bending of Sheet

In the V-bending fabricationg, scratches caused by the contact of the die shoulder radius and the sheet metal are produced on the sheet metal surface. The scratch shape can be qualitatively assessed from the results calculated by FEM. The size of the scratching is determined by the V-bending condition and the sheet metal properties. It is caused by varying the motion of the material on the V-bending and the contact area between the die and the sheet metal. The scratches need to be evaluated by the width, the height, and the depth, and classified based on the different ways it is produced. Both the scratch height and depth can be evaluated from FEM results qualitatively. The scratch width almost corresponded with the contact area between the die and the sheet metal. From these results, the scratch width can be estimated from the calculated sheet metal motion on the V-bending. However, there are differences between the calculated and FEM contacted distance. The theoretical analysis needs to induce the sheet metal properties in order to make progress in predicting accuracy of the contact area.