The Contrasting and Statistics of Spreading Area Data in Soldering Wettability

It is a serious issue if we can get a reliable result or not when conducting and summarizing an experiment. Sometimes it is not enough by diagrams only. It is a good way to use mathematical regressive method for confirming and checking the correctness of diagrams. Taking correlation between three variables (Ni content, temperature, time) and solder spreading area as example, the diagrams and regressive equations were discussed in this paper. The diagrams give the results that the spreading area increases with the temperature increase. But it is not clear about the factors Ni content and soldering time. When using the step by step regressive method to calculate, the equations were got. They indicate that Ni content and soldering time have pronounced mutual effect on the function, temperature has quadratic or line effect in Sn-3Ag-0.5Cu or Sn-3Ag-0.5Cu-0.2Co solder alloy respectively, and the correlations are both positive