Process Studies on Laser Welding of Copper with Brilliant Green and Infrared Lasers

TLDR

Copper is difficult to weld with lasers because of its high thermal conductivity and low room‑temperature absorption, which require high intensities and make the process sensitive to surface conditions, but green laser radiation has a higher absorption that lowers the threshold for deep‑penetration welding. The study examined how the green wavelength affects energy coupling in heat‑conduction and deep‑penetration welding and its impact on weld shape.

Abstract

Copper materials are classified as difficult to weld with state-of-the-art lasers. High thermal conductivity in combination with low absorption at room temperature require high intensities for reaching a deep penetration welding process. The low absorption also causes high sensitivity to variations in surface conditions. Green laser radiation shows a considerable higher absorption at room temperature. This reduces the threshold intensity for deep penetration welding significantly. The influence of the green wavelength on energy coupling during heat conduction welding and deep penetration welding as well as the influence on the weld shape has been investigated.