06

Poor Lead Solderability
During wave contact the solder has failed to wet the surface of the lead although there is evidence of satisfactory wetting on the pad. This problem was caused by marginal solderability of the leads and the age of the 10% solids flux being used in production. Replacing the flux and changing it regularly after forty hours of operation solved the problem. Flux in an open tank degrades; its performance changes even if the solids content remains the same. Using components and making sure they are rotated in stores also reduces the issue reoccurring. Component suppliers generally only guarantee their parts are solderable for a period of twelve months.