Bottle-shaped can manufacturing method

A bottle-shaped can manufacturing method for forming a shoulder portion and a neck portion integrally by working a bottom side of a bottomed cylindrical can formed thinner at a trunk wall than at a bottom wall by drawing and ironing a metallic sheet, comprising:

• a diametrically small cylindrical portion forming step of:
• drawing the bottom wall and a portion of the trunk wall adjacent the bottom wall into (i) a diametrically small bottomed cylindrical shape having a diameter less than a diameter of a remaining portion of the trunk wall and (ii) a curved face of the shoulder portion by applying pressure on a bottom corner portion with a forming pusher having an outer face shape corresponding to a shape of the curved face of the shoulder portion to be formed and a drawing die having an inner face shape corresponding to the shape of the curved face of the shoulder portion to be formed by holding the curved face of the shoulder portion with the forming pusher and the drawing die simultaneously;
• another diametrically small cylindrical portion forming step of:
• re-drawing the diametrically small bottomed cylindrical shape into a diametrically smaller bottomed cylindrical shape and holding the bottom corner portion by at least one of a blank holder having a predetermined tapered face, a re-drawing die having a tapered face, and a re-drawing punch diametrically smaller than the re-drawing punch;
• and
• a shoulder portion reforming step of:
• pushing and extending the shoulder portion formed by said diametrically small cylindrical portion forming steps after a diameter of the diametrically smaller bottomed cylindrical shape is substantially equal to a diameter of said neck portion by executing drawing working of the another diametrically small cylindrical portion forming step one or two more times.

A bottle-shaped can manufacturing method for forming a shoulder portion and a neck portion integrally by working a bottom side of a bottomed cylindrical can formed thinner at a trunk wall than at a bottom wall by drawing and ironing a metallic sheet, comprising:

• a first diametrically small cylindrical portion forming step of:
• drawing the bottom wall and a portion of the trunk wall adjacent to the bottom wall of the bottomed cylindrical can into (i) a diametrically small bottomed cylindrical portion having a diameter less than a diameter of a remaining portion of the trunk wall and (ii) a curved face of a lower part of the shoulder portion of the bottle-shaped can to be formed, by applying pressure on a bottom corner portion of the cylindrical can with a forming pusher having an outer face shape corresponding to a shape of the curved face of the lower part of the shoulder portion of the bottle-shaped can to be formed, a drawing die having an inner face shape corresponding to the shape of the curved face of the lower part of the shoulder portion of the bottle-shaped can to be formed, and a drawing punch configured to urge a portion of the bottom wall into the drawing die while holding the portion of the trunk wall adjacent to the bottom wall between the forming pusher and the drawing die;
• a second diametrically small cylindrical portion forming step of:
• re-drawing a bottom portion and a cylindrical portion of the trunk wall adjacent to the bottom wall of the diametrically small bottomed cylindrical portion and a repetition of re-drawing a diametrically smaller bottomed cylindrical portion to be formed with each of a plurality of pushers each having a tapered face, mating re-drawing dies each having correspondingly tapered faces and mated re-drawing punches having different diameters, until a bottomed cylindrical portion having a diameter equal to a diameter of the neck portion and extending into a shoulder wall continuing from the curved face of the lower part of the shoulder portion is obtained;
• and
• a shoulder portion reforming step of:
• pushing and smoothing the curved face of the lower part of the shoulder portion and the extended shoulder wall.