Process for manufacturing a can with a polygonal cross section and a can with a polygonal cross section

A process for manufacturing a can body with a polygonal cross-section, comprising the steps of:

• forming, from a metallic sheet, a tubular body having a cylindrical lateral wall with upper and lower ends and a longitudinal seam;
• milling the cylindrical lateral wall of the tubular body to form a plurality of circumferential ribs transverse to the longitudinal axis of the tubular body between the upper and lower ends of the tubular body which ribs are continuous and axially spaced from each other and defined by a degree of radial plastic deformation of the respective circumferential region of the cylindrical lateral wall of the tubular body;
• expanding the tubular body with said axially spaced circumferential ribs to form a can body of a desired polygonal cross-section having a plurality of walls with two adjacent walls connected at a corner;
• deforming the can body of polygonal cross-section during the expanding step to form at each corner of the polygonal can body a continuous straight region in the axial direction of the can body for the entire length of the can body between its upper and lower ends with the circumferential ribs being eliminated from the longitudinal regions;
• and
• seaming a bottom and an upper wall of the can to the body of polygonal cross-section.