Working of sheet metal

Abstract

A method of manufacturing a formed sheet metal structure having a final formed sheet metal shape includes the steps: providing a sheet metal workpiece A; plastically deforming the workpiece to provide an intermediate formed sheet metal shape B. The intermediate shape comprises a first pattern of at least three creases C1, C3, C4, that meet at a first non-developable vertex NDV1, C, and a second pattern of at least three creases C2, C5, C6, that meet at a second non-developable vertex NDV2. Then bending the workpiece to carry out one or more of: (i) moving one or more of the creases within the workpiece; (ii) removing one or more of the creases; (iii) adding one or more further crease that meets other creases at the first and / or second non-developable vertex. In this way, the geometry of the first and / or second non-developable vertex is changed to provide the final formed sheet metal shape for the formed sheet structure. The plastic deformation may use a main anvil tool, a main forming tool, an auxiliary anvil tool, and an auxiliary forming tool (Figure 3A). The auxiliary tools may carry out shear material transfer in the workpiece to get the NDV1 and NDV2. [Figure 15]