GB1320640A - Laser welding method - Google Patents

Abstract

1320640 Welding by fusion COMPAGNIE GENERALE D'ELECTRICITE 29 Sept 1971 [29 Sept 1970] 45338/71 Heading B3R Point or short line welding by continuous laser beam, without beam interruption, is effected by pre-heating with an unfocused portion of the beam, effecting local fusion with the beam focus, and annealing with an unfocused portion of the beam. As shown, a cylindrical beam from a continuous laser, such as gas (e.g. CO 2 ), liquid or solid state, is focused by a lens 10 to provide a cylindrical focus 5. Metal workpieces 1, 2 are successively moved from a position A where they are placed in contact, through a position B in the beam convergent portion to effect the pre-heating, the beam focus C to effect fusion at and around a point 3, and a position D in the beam divergent portion to effect the annealing, to a weld completed position E. At the preheating stage the workpieces may be held stationary or moved towards the fucos at a speed such that the pre-heating is effected before the focus is reached. At the fusion stage, the workpieces may be held stationary or slowly moved along the focus cylinder. The welding may be automated, new workpieces being moved into the position B on completion of annealing, e.g. before the welded workpieces are removed from position D. In alternative embodiments, the workpieces may be moved in reverse direction to that shown; the positions B and D may be on the same side of the focus; and the workpieces may be fixed with the lens being moved or a variable focal length lens used. The lens 10 may be circular for point welding or cylindrical for short line welding.