The present invention increases the strength and durability of the ball itself, it can be performed easily and in a short period of time clean welding process, and a simple configuration, is suitable for mass production, and to provide an economical Somi ball chain. The apparatus includes a narrow band plurality of balls 1 formed into a hollow sphere shape by plastic deformation of the plate-shaped ball for the base material, Somi for ball consisting of a plurality of connecting rod 5 for connecting the ball 1 mutual to next set A chain S, the seam line portion of the ball 1 which is formed by the left and right side edges of the ball substrate is butt-shaped, it is necessary in accordance with the point-like laser welding unit 2 by laser welding machine seam line Providing a plurality at intervals. .BACKGROUND 5
展开▼
