Method and apparatus for laser beam welding of longitudinal seams in container bodies

A method for laser beam welding of longitudinal seams in container bodies having predetermined circumferential dimension, the method comprising:

• providing a metal sheet having opposing first and second longitudinal ends, and opposing first and second transverse ends, the first and second longitudinal ends each having a length, a longitudinal edge, and an inner face and an outer face, and the first and second transverse ends each having a length which exceeds the predetermined circumferential dimension for each container body;
• getting the first longitudinal end over the second longitudinal end, either during or after shaping of the container body, into a position, to form an acute angle and define an angular opening therebetween, which angular opening extends longitudinally along the length of the first and second longitudinal ends, by moving the longitudinal edge of the second longitudinal end toward the inner face of the first longitudinal end;
• aiming at least one focused laser beam into the angular opening and causing relative movement between the focused laser beam and the angular opening along the longitudinal extension of the angular opening thereby defining a feed direction;
• heating at least a portion of the inner face of the first longitudinal end and at least a portion of the outer face of the second longitudinal end with the at least one focused laser beam to a temperature above the temperature which is effective as a welding temperature;
• and
• pressing together the inner face of the first longitudinal end and the outer face of the second longitudinal end while the respective faces are at or above the welding temperature, thereby forming a welded longitudinal seam.