What are the main qualification tests for using liquid flux?
The main qualification tests that will be required will be to determine adequate hole-fill in relation to board and component finishes. No-clean fluxes will be less active and require particular attention, when compared to water washable organic acid fluxes, which will exhibit the best hole-fill. Having optimized preheat temperatures, solder pot temperatures, and flux volume, the conveyor speed may have to be reduced to accommodate the solder wetting when using lead-free solder. The flux will play an important role in maintaining production yields. Lower solids fluxes may require faster conveyor speeds to avoid complete flux burn-off, higher solids fluxes will be more forgiving and conveyor speeds may not have to be reduced.
