Working of sheet metal

A formed sheet metal structure, obtained by:

• providing a sheet metal workpiece having first and second surfaces opposed to each other and at least one edge;
• bending the workpiece to form at least a first sidewall portion defined between the edge and a basal region, the first sidewall portion thereby defining a curved fold region in the sheet metal workpiece adjacent the first sidewall portion;
• providing a first anvil tool with a tool surface for contact with and constraint of the first surface of the sheet metal workpiece;
• providing a first forming tool with a tool surface for contact with and constraint of the second surface of the sheet metal workpiece;
• contacting the sheet metal workpiece with the anvil tool and the forming tool, and progressively sliding the forming tool and/or the anvil tool along the curved fold region to cause shear material transfer in the curved fold region to further deform the curved fold region.

Sheet metal working apparatus suitable for performing a method for manufacturing a formed sheet metal structure, the method comprising:

• providing a sheet metal workpiece having first and second surfaces opposed to each other and at least one edge;
• bending the workpiece to form at least a first sidewall portion defined between the edge and a basal region, the first sidewall portion thereby defining a curved fold region in the sheet metal workpiece adjacent the first sidewall portion,
• the apparatus comprising:
• a first anvil tool with a tool surface for contact with and constraint of the first surface of the sheet metal workpiece;
• a first forming tool with a tool surface for contact with and constraint of the second surface of the sheet metal workpiece,
• the apparatus being operable to bring the sheet metal workpiece into contact with the anvil tool and the forming tool, and progressively sliding the forming tool and/or the anvil tool along the curved fold region to cause shear material transfer in the curved fold region to further deform the curved fold region,
• and wherein the first anvil tool and first forming tool are configured to be moveable so as to maintain (i) a fixed distance between the forming tool and the anvil tool, or (ii) a fixed force on a sheet metal workpiece disposed between the forming tool and the anvil tool.