Comparative analysis of spring back behaviour in V-bending sheet plates with oval holes

Sheet metal materials which are shaped by bending are used in many areas such as aerospace, household appliances, defence, automotive, medical device industries. Sheet metals experience a few problems after bending. By far, the most important problem is bending. After bending, the sheet bends into a different angle than the desired angle which is called springback. In order to overcome springback, it must be correctly predicted before bending. Springback results with time and financial loss. So some processes are done in order to minimize springback like overbending or reverse bending. In this thesis, hole and thickness effect on springback is investigated. As testing material DKP sheet metal is used. Parts are cut by laser which are 60x80 cm in size. Parts are selected in a way that springback effect can be seen clearly. The holes in materials are cut according to the ratio of hole lenght divided by material length. In this manner hole ratios are selected as 30, 40 and 50% and holes are also cut by laser cutter. Material thicknesses are selected as 1, 1.5 and 2 mm. Parameters such as bending radius, temperature, punch radius are constant while thickness and hole ratios are chosen as parameters. In this dissertation, 5 experiments are conducted for each specimen. Results are interpreted with respect to the hole ratios and thicknesses. The results are compared with the results in the computer simulations which are done with Simufact.