There has been a push in the automotive and aerospace industries towards die-less forming processing that are able to reduce both part cost and part energy. Incremental forming is a die-less forming process that fabricates parts using hemispherical tools following a tool path (similar to that found with conventional milling operations), that slowly deforms the sheet metal into the final desired configuration. Global springback for incremental forming, as defined herein, occurs after the part is unclamped from the retaining fixture. This form of springback is currently a significant impediment to the process since, when the part is released, the residual stresses created during the forming process result in significant part distortion and thereby, undesirable part geometries. To reduce this issue, this paper examines the effect on direct electric current on residual stress and springback elimination when applied post forming, which previous work has shown the potential to reduce this issue. This work is an extension of previous work resented at MSEC 2015. The previous work examined applying electric current to areas of high residual stress through the material’s thickness. This work examines the effect of applying electric current along the length and width of a part (path testing). This work concludes that running multiple paths increases springback reduction and the order in which the path testing is conducted has very little appreciable effect on the springback reduction during path testing.

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.