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Poor Hole Fill
Poor or incomplete hole fill is normally a fluxing or heating issue, it is uncommon to be a printed board problem. In the example shown the poor hole fill is due to pre heat settings. The solder has wetted the leads of the device but failed to wet the surface of the through hole. As a guide the topside temperature of the printed board just before wave contact should be 100-110oC. This is generally true for double sided and multilayer boards. Single sided boards will be processed at slightly lower temperatures as no solder penetration is needed.