| 摘要 |
<p>A production method for a bottle type can, which uses as a blank a bottomed cylindrical can having a barrel wall thinner than a bottom wall and formed by drawing a metal thin sheet and subjecting the drawn sheet to thin-walling consisting of at least one of bending/elongating and ironing, and which integrally forms a shoulder portion having an inclined surface and a mouth/neck portion in a small-diameter cylinder shape by working on the bottom side of the can, the production method comprising a step of preforming the bottom corner portion of the can into a shoulder curved surface arcuate in longitudinal cross-section, a first small-diameter cylindrical portion forming step for drawing the bottom of the can into a bottomed cylindrical shape smaller in diameter than the barrel with the shoulder curved surface subjected to blank-holding, a second small-diameter cylindrical portion forming step for further drawing the bottomed cylindrical portion drawn from the can bottom into a smaller-diameter bottomed cylindrical shape with the bottom corner portion kept blank-held, and a shoulder portion re-forming step for forming by extrusion/elongation the shoulder portion formed by the first and second small-diameter cylindrical portion forming steps into a smooth inclined surface continuing from the shoulder curved surface on the barrel side after the diameter of the bottomed cylindrical portion obtained following at least one second small-diameter cylindrical portion forming step is reduced to approximately the same as that of the mouth/neck portion.</p> |
