The latest generation of high-brightness disk and fiber lasers allows deep penetration welding with a weld seam width of a few 10µm and an aspect ratio of up to 15. Welding speeds exceeding 60m/min are achieved. These properties are very promising for high-productivity joining of small parts like thin sheet and fine tubes with a thickness of up to 1 mm as frequently used in the electronic, automotive and medical industries.
For a reliable production not only the machinery and tools like axes and clamping devices have to be adapted to the high welding speed and to the small weld dimensions, but also the process monitoring system sampling rate must be increased in order to get enough information per weld seam length.
This paper presents a multi sensor system which is capable of monitoring the achieved weld quality of fine tubes and of detecting typical welding errors such as humping and the formation of blowholes.