Producing isolated shrink corners by folding-shearing

A novel sheet forming technique, folding-shearing, is used to produce shrink corners with minimal sheet metal wastage. The limiting height of shrink corner – a key feature of many parts - is investigated through a wide a range of experimental trials and FEA simulations. Folding-shearing can produce a shrink corner over twice as tall as can conventional stamping with a blankholder. The eventual limit is necking followed by fracture and the influence of part size and material, die spacing, blank profile and ‘shear zone angle’ on necking is demonstrated, alongside insights from a simple force model.