Manufacture of tunnel-shaped sheet metal parts with improved accuracy using novel toolpath strategies for single point incremental forming

Single point incremental forming is a novel sheet metal forming process that crafts 3D shapes out of sheet metal using layerwise deformation of the metallic sheet with a simple tool, which is typically cylindrical with a hemispherical ball-end. In this work, a combination of intelligent clamping and toolpath strategies was used to manufacture tunnel-shaped parts using aluminium alloy, AA1050AH14. The toolpath strategies helped improve on the low forming limits for failure typically associated with the manufacture of such shapes. A new method for compensating the inaccuracies in the parts caused by springback and other plastic deformations associated with the process using predicted 2D sectional views was also tested. The predicted sectional views were generated using training sets from the scanned geometries consisting of large datasets of point clouds. The training sets helped generate multivariate regression equations which were then used to create the predicted sections. The predicted sections were interpolated to create compensated geometries which then enabled part manufacture with improvement in accuracy. The result from this new strategy was compared with improvements observed in 3D compensation followed by adaptive pocketing and contouring toolpath strategies.