| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of machining a sealing cap for a sealed type battery, in which adhesion strength is improved, parts are made lightweight and the cost reduction is attained. SOLUTION: In the machining method of a sealing cap for a sealed type battery, a disk-shaped sealing cap 1 is set at a prescribed position of a die 5, the upper end face or the bottom face of an inner cylindrical part 3 with the center hole 2 burring-processed is pressurized by a punch 6, and machining is performed so that the radius value R of the inner circumferential edge 4 at the lower end of the inner cylindrical part 3 is smaller than the thickness t of the sealing cap 1. Additionally, it is desirably formed so that the length L of the inner cylindrical part 3 is slightly longer than the finish dimension, and it is desirably finished so that the radius value R is 1/3 or less of the thickness t.
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