Thermal reliefΒΆ
In the above figure there are two examples. The first example is a through pole pin without thermal reliefs, and the second example a through hole pin with thermal reliefs. In the first example there will be problems when the through hole is soldered. Because the through hole pin and pad are fully surrounded with copper, and copper is a good thermal conductor, all the heat needed to solder the through hole properly will directly flow to the surrounded copper. In the second example there are four cut outs around the solder pad. Because the pad is not fully surrounded with copper, the through hole pin will solder properly.