An experimental analysis of the relationship between the corner, die and punch radii in forming isolated flanged shrink corners from Al 5251

Horton, P. M.; Allwood, J. M.; Cleaver, C.; Nagy-Sochacki, A.

Knowledge of geometry based forming limits would be beneficial early in the product development process to enable design for manufacture in sheet metal forming process. This paper investigates the influence of corner, die and punch radii on the limiting part depth for drawing an isolated flanged shrink corner from aluminium sheet with and without a blank holder. Trends are identified to establish whether complex component geometry can be analysed to provide a guide for process limits for drawing. The failure draw depth is determined experimentally with a configurable tool for 96 different drawing scenarios. A further 432 scenarios were analysed using a validated Finite Element model. The results demonstrated that a trend could be obtained through plotting the failure draw depth against the average radii of a shrink corner. Assuming this can be extrapolated to full parts, the trend could be useful in the early stages of component design to guide decision making for the components shape and selecting the most appropriate manufacturing process.