PCB焊点焊接缺陷原因分析

PCB solder welding defect cause analysis

PCB焊点焊接缺陷产生的原因可能很多,如果你从扩散焊接的特点考虑就会变得明了起来!熔化的焊料原子沿着被焊接金属的结晶晶界的扩散,扩散所需要的激活能也可称为"表面自由能"比体扩散小。一般锡料的活性能约为380达因/厘米,鲜活的铜面在助焊剂的辅助下约为1265达因/厘米,所以焊接可以良好进行。

There may be a lot causes of PCB solder welding defects. However if you consider from the characteristics of diffusion welding, it will become clear! The crystallization of molten solder atoms spreads along the weld metal grain boundary diffusion. The spreading needed to activate can also be referred to as the Surface Free Energy than the body of the diffusion. The activity of general tin material can be approximately 380 dyne/cm, and lively copper surface under the auxiliary of lfux is about 1265 dyne/cm, so welding can be performed well.