Effect of finishes of oxygen-free copper on laser welding cracks

Utlilizing 300 W Nd:YAG laser with the wavelength of 1.06 μm for laser weld to study the effect of electroless plating and electroplating on the weldability of oxygen-free copper shell microwave module. Based on the orthogonal test of five factors and four levels as well as setting multiple-pulse waves to match laser weld technological parameters, the typical laser weld technological parameters are established. By using the above-mentioned typical parameters, a beautiful, homogeneous microstructural, and sealed weld seam can be obtained. It is studied that the difference of electroplating technology has great effect on the quality of weld seam. When electroless plating nickel, there exists P can vaporize easily and form multiple low-melting compounds, which increases the tendency of cracks during solidification. When electroplating nickel, there existis no any P, which can form well-shaped weld seam without cracks. The seal test shows that the air impermeability of oxygen-free copper microwave module is below 5×10^-9Pa·m³/s, the one-off qualified rate of product is above 95%.