| 摘要 |
PROBLEM TO BE SOLVED: To provide a forming method capable of precisely and efficiently forming a raw material metal sheet into a square battery case by means of both machining of drawing and ironing.SOLUTION: When a first intermediate cup body 2 of an elliptical cross-sectional shape obtained by subjecting a raw material metal sheet to drawing machining is subjected to redrawing machining, in such a state that a sleeve 15 fit to a punch 13 is inserted along an inner wall surface 2a of the first intermediate cup body 2, thereon, the sleeve 15 is stopped on the insertion position as it is, only the punch 13 is advanced in a die 14 to perform the forming, a second intermediate cup body 3 of a rectangular cross-sectional shape is formed, the second intermediate cup body 3 is further subjected to ironing machining and a square battery case is formed. |
