Impact of soldering terminal solderability of component and PCB on solder joint interface

The soldering terminal solderability of component and printed circuit board (PCB) has a strong impact on the formation of solder joint interface. The good solderability of the soldering terminal will result in good interface and high reliability of solder joint. The poor solderability of the soldering terminal will result in undesirable interface of solder joint, poor wetting from macrostructure, many micro cracks at interface from Microstructure, because the solder is hindered during diffusion process. In this paper, the impact of soldering terminal solderability of component and PCB on solder joint interface were illustrated by two experiments. In experiment 1, the through-hole components that were known poor solderability were coated tin by hot dip method, then compared the solderability and the interface quality of the components before and after coating tin. In experiment two, bought new component and PCB, oxidized some components and some PCBs, then tested the solderability of new components and PCBs as well as the oxidized components and PCBs with tester Metronelec ST88, and got the solderability curve and the quantized data of the surface; soldered these new components and oxidized components with new PCBs and oxidized PCBs In combination, got the solder joints with different soldering quality, judged the crack degree and the reliability of the soldering interfaces through combining SEM analysis with quantitative solderability data, and analyzed the relationship between the solderability and the reliability in order to guide the actual production.