High-quality laser welding of copper using appropriate power modulation

Abstract

Due to its very good electric and thermal conductivity, copper is an important material with a wide range of applications, which require an efficient and reliable welding process, preferably with laser beams. The same material properties make laser welding of copper a challenging task. To achieve welds with penetration depths of several millimeters in copper using commercially available laser sources relatively low feed rates below 10 m/min are needed. Welds in copper at such low feed rates with 1 µm wavelength lasers often suffer from numerous weld seam defects such as melt ejections and pores.In this paper welds in copper using different laser wavelengths will be presented. Due to a higher absorption green laser light (515 nm wavelength) is obviously far better suited for welding copper. Hence the potential of green laser light on welding copper is discussed. Furthermore the influence of power modulation during copper welding on weld defects is shown. Presuming the correct parameters, modulation of the power shows very distinct advantages. On the one hand a strong reduction in number of weld defects was measured. On the other hand a significantly more regular and homogeneous solidified weld seam surface for the modulated welds was achieved. Welding results for different copper alloys using laser power modulation with different laser wavelengths are presented. Furthermore the influence of the modulation frequency is discussed.Due to its very good electric and thermal conductivity, copper is an important material with a wide range of applications, which require an efficient and reliable welding process, preferably with laser beams. The same material properties make laser welding of copper a challenging task. To achieve welds with penetration depths of several millimeters in copper using commercially available laser sources relatively low feed rates below 10 m/min are needed. Welds in copper at such low feed rates with 1 µm wavelength lasers often suffer from numerous weld seam defects such as melt ejections and pores.In this paper welds in copper using different laser wavelengths will be presented. Due to a higher absorption green laser light (515 nm wavelength) is obviously far better suited for welding copper. Hence the potential of green laser light on welding copper is discussed. Furthermore the influence of power modulation during copper welding on weld defects is shown. Presuming the correct parameters, modulation of the ...