Investigating the buckling deformation of thin metal sheets during the blanking process

Abstract

This article describes the effect of the generated stresses due to the cutting process on the possibility of the occurrence of buckling deformation in a thin sheet, which could affect the performance of the cut part, especially for some applications such as the cutting of the thin sheet laminations of motor parts. To achieve the research objectives, an experimental approach was followed. Two different thicknesses and two-grain orientations of silicon steel material were applied to investigate the influence of thickness and grain orientation upon the induced buckling deformation. Blanking dies were designed to cut thin sheets of steel at different cutting speeds. Buckling height was measured optically using a 3D microscope with regard to the cutting parameters. The results showed the appearance of buckling deformation only at low sheet thickness. The maximum buckling height was about 164 µm (82% of the material thickness) in the transverse grain direction at the lower cutting speed. Meanwhile, the results also demonstrated the presence of an elongation in the material of approximately 90 µm (1.8%) on the cutting sides, which played a role in the application of pressure to all sides of the cut plate, resulting in the formation of a plastic buckling deformation prior to the completion of the cutting process, and thus the occurrence of the buckling phenomenon.