Solder bar and solder wire defect analysis ------ pinholes and pores, in appearance, the difference between pinholes and pores in the diameter of the pinholes is small, now on the surface, you can see the bottom. Pinholes and pores represent that there are bubbles in the solder joint, but it is still extended to the surface, most of which occur at the bottom of the substrate, when the bottom of the bubble is fully diffused and the money has been condensed, that is, pinholes or pores are formed. The reasons are as follows: