Springback Induced in Single Point Incrementally Formed 2024-T3 Aluminum of Various Thicknesses

Abstract

Incremental forming (IF) is sheet metal process proving to be of particular interest in industry as a method to create complex geometries. The technology offers the flexibility to create complex geometry on drafted profiles without the necessity of a forming die, which offers unique advantages over die forming processes, including: significantly reduced lead time, eliminating initial die costs and the need to retain the die after the products life cycle is complete, which can be significant, and the ability to modify the geometry with relative ease throughout the product’s life cycle. During incremental forming, the material’s local plastic deformation induces high residual stresses into the workpiece, causing significant springback once it is released from the clamping fixture used to hold the workpiece stationary during forming. Different material thicknesses result in different degrees of springback on the workpiece. This is due in part to the change in section modulus of the formed part. Thicker materials will have a larger section modulus and therefore not be if two different material thicknesses undergo equal deformation, the thinner material will experience greater elastic recovery, or springback. If incremental forming is to ever reach industry level applications, the material’s springback behavior at a variety of thicknesses must be characterized. Having the knowledge of the resulting springback is necessary for further research to be conducted on incremental forming in order to reduce or eliminate springback. Also, it is important for designers and engineers to design products within the capabilities of the technique. This paper investigates the springback present in 5 thicknesses of 2024-T3 clad aluminum subsequent to incremental forming and release from the forming fixture. It is found that as material sheet thickness increases and the specimens are formed to the same internal geometries, springback after releasing from the clamping fixture decreases, and variation in springback between equal thicknesses decreases.