Experimental and numerical investigation of the effects of hole presence on springback in the bending zone in sheet metal

Sheet metal products formed by bending are widely used in various industries, including the plane and automotive sectors, as well as household appliances, defense industry, precision devices, medical devices, and aerospace. One of the significant challenges in bending sheet materials is springback. The deviation of sheet parts from the desired angle after bending can lead to substantial time and cost losses in industries. Therefore, various methods are employed to minimize springback. To eliminate springback, it is essential to predict the springback that will occur after bending. Once springback is accurately predicted, corrective methods are applied, such as additional bending or reverse bending. This study investigates the effects of holes on sheet metal springback in perforated and non perforated sheets of different thicknesses. AISI 304 stainless steel sheet is used as the experimental material, and the parts are cut into dimensions of 100mmx200mm using laser cutting. The hole ratios in the samples were determined as the amount of holes and the ratio of the length of the sample. Hole quantities of 0%, 10%, and 30% are selected and processed with laser cutting. The thicknesses of the parts are determined as 1mm and 2mm. During the V-bending process, parameters such as temperature, stationary die radius, and clamping force are kept constant, while thickness, clamping force time, and hole ratios are selected as variable parameters. Experiments are conducted for each sample in this study. The results obtained are used to compare the springback of perforated materials with non-perforated materials, and the impact of holes on springback is examined. The obtained results were compared with Finite Element Method (FEM) analysis results.