An Exploration of the Process Operating Window for Folding-Shearing in a Press-Tool

Folding-shearing, is a novel process, which in previous work has been used to create isolated shrink corners. The top surface of a blank was clamped, and the part formed by manual folding followed by a shearing process. For the first time, this paper demonstrates folding-shearing in a press-tool. A single set of tooling is used to crash form the upper surface of the part, followed by folding and in-plane shearing with all tools moving vertically, avoiding any requirements for cams or other mechanisms. The results of the paper demonstrate that folding-shearing can be implemented in a conventional press-tool. A process window is defined by process parameters and is limited by springback, thinning or thickening. These limits are influenced by process parameters including part radius, feed radius, fold geometry, part height and material parameters. An analytical description of the mechanics of the process is proposed and is validated though finite-element simulations and experimental trials.