| 摘要 |
A patterned sheet (13) having two long sides is wrapped around a mandrel (89 ). The mandrel is provided with at least one flat surface. The long sides of th e sheet are secured adjacent to the flat surface of the mandrel and points alo ng the long sides of the sheet are connected by laser welding or other connecti ng means. The laser beam (28) is directed substantially perpendicular to the welding plane of the points to be welded, even if the weld points do not all lie on a single line parallel to the mandrel's longitudinal axis. |
