Patent ID: 7820938

Claim:
In a continuous line processing installation, a method for butt welding two bands running successively along a longitudinal direction, using a laser beam and without using filler material, the method comprising the steps of: calculating an offset based on the thickness of the bands to be welded, while taking into account the degree of accuracy of the positioning, and of the cutting, of two edges to be butt welded, the offset being counted as positive or negative in order to be subtracted or added to a reference distance; calculating a travel distance from the reference distance and the calculated offset; in the running direction, holding a downstream end of a first band in a first double-jaw clamp and an upstream end of a second band in a second double-jaw clamp to immobilize the downstream end of the first band and the upstream end of the second band; while immobilized, cutting the downstream and upstream ends to provide, respectively, a first rectilinear cut edge and a second rectilinear cut edge parallel to the first rectilinear cut edge, each of the first and second cut edges being spaced away from an end of the jaws of the corresponding double-jaw clamp by an overhang distance; separating the first and second cut edges by the reference distance, whereby, since the butt weld is created without using any filler material, the reference distance is unrelated to any material thickness of a filler material; displacing at least one of the first and second double-jaw clamps towards the other one of the first and second double-jaw clamps to obtain a final welding position, the total amount of relative displacement being equal to the calculated travel distance, the final welding position defining a gap between the cut edges having the same sign, positive or negative, as the calculated offset; and passing the laser beam along a contact plane between the cut edges to make a welding bead without using a filler material.