| 摘要 |
PROBLEM TO BE SOLVED: To provide a polygonal can which can be molded from a cylindrical can capable of attaining decorative effects equivalent to those of the cylindrical can without forming any bend or distortion in a boiler drum side wall. ! SOLUTION: A can bottom outer peripheral part A-2 scheduled to become a straight part B-2 of a polygonal can B is moved radially inward by a pressing tool, and an outer peripheral part A-1 of the can bottom scheduled to become a corner part B-1 of the polygonal can is moved radially outward by an expansion tool, so that the shape of the can bottom part is deformed into a shape corresponding to the transverse section of the polygonal can so that the peripheral length of the can drum may be substantially unchanged before and after the deformation. ! COPYRIGHT: (C)2015,JPO&INPIT |
