Copper laser welding breakthrough for Trumpf

Trumpf has pulled off what experts had previously said was impossible; the laser welding of copper sheets.

In a one-off experiment, Trumpf specalists were able to weld two 3 mm thick copper sheets together to a depth of 5 mm as an overlap join with excellent seam quality using a combination of disk lasers of varying laser power. No one has ever been able to do this before.

As a highly reflecting material, copper is extremely difficult to weld. In most cases, undesirable side effects occur, including blowholes in the weld seams.

The specialists connected together three disk lasers with 4 kW, 6 kW and 8 kW laser output using a special fibre coupler. Over 16.5 kW was brought to bear on the workpiece. The resulting welding speed of 1.8 m/min stabilised the dynamic melt pool common to copper. For this experiment to be both secure and successful, the disk lasers had to be finely synchronised, an accomplishment supported by the Trumpf Laser Network (TLN).

More powerful lasers to be offered in December 2006 will permit even greater welding speeds and an expanded process window with consistent seam quality, says the company.

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