LASER MICRO WELDING OF ALUMINUM WITH THE SUPERPOSITION OF A PULSED DIODE LASER AND A PULSED ND:YAG LASER

摘要

Pulsed laser welding with Nd:YAG lasers is appliedfor welding of thin aluminum sheets when the heataffected zone has to be minimized. Due to the pulsedoperation of the Nd:YAG laser and the lowabsorptivity of aluminum for infrared radiation(～5 % @ 1064 nm) the achieved welding speed issmall in comparison to continuous laser weldingprocesses. In this study, a conventional pulsedNd:YAG laser is superposed with a diode laser(output power up to 100 W) to weld AlMg1 sheetswith a thickness of 1.5 mm. The diode laser operatesat a wavelength of approximately 808 nm in order tomeet the absorption maximum of aluminum at thiswavelength (～15 % @ 808 nm). The diode laser isemitting laser pulses with a pulse length of up to 200ms which are synchronized with the laser pulses ofthe Nd:YAG laser. With this combination an increasein penetration depth has been achieved due to preheatingof the diode laser.