PRODUCTION METHOD FOR BOTTLE TYPE CAN AND FORM-WORKING TOOL

摘要

A bottle-shaped can manufacturing method for forming a shoulder portion having a slope and a diametrically small cylindrical neck portion integrally by further working a bottom side of a bottomed cylindrical can which is formed thinner at its trunk wall than at its bottom wall by drawing a metallic sheet having a thickness of 0.1 to 0.4 mm and by executing at least one thinning working of a bending/extending working and an ironing working. This method comprises: a step of preforming a bottom corner portion of the can into a curved shoulder face having an arcuate longitudinal section; a first diametrically small cylindrical portio n forming step of drawing the bottom of the can into a diametrically smaller bottomed cylindrical shape than the trunk portion, with the curved shoulder face of the bottom corner portion being unwrinkled; a second diametrically small cylindrical portion forming step of drawing the bottomed cylindrical portion drawn from the can bottom into a diametrically smaller bottomed cylindrical shape, with the bottom corner portion being unwrinkled by the surface of a tool; and a shoulder portion reforming step of pushing and extending the shoulder portion, which is formed by the first diametrically small cylindrical portion forming step and the second diametrically small cylindrical portion forming step into a smooth slope leading to the curved shoulder face on the trunk side, after the diameter of the bottomed cylindrical portion formed by executing the drawing working of the second diametrically small cylindrical portion forming step once or two or more times becomes substantially equal to a diameter of the neck portion. The invention further provides a forming tool for effecting the bottle-shaped can manufacturing method.