Product Code: JLA_16_3_134

Authors:
S. Amorosi
Th. Sidler
R. P. Salathe´
Advanced Photonics Laboratory, Ecole Polytechnique Fe´de´rale de Lausanne, Switzerland

H. P. Schwob
J. Hertzberg
LASAG AG, Thun, Switzerland

We describe a novel procedure for highly reliable microspot welding of copper based on a calibrated on-line reflectivity measurement. This parameter is used to control the laser power slope and the weld spot diameter. Reliable welds are obtained without the need of other active control mechanisms. The new technique allows realizing welds with a diameter close to the laser beam waist and leads to a reduction in the relative standard deviation of the molten pool diameter from 20% to about 3%. © 2004 Laser Institute of America.