I would be far more concerned about the flux residue intentionally left on the board than the �dust bunnies� sticking to the flux. In �perfect� no-clean applications, flux residue, although present, is nearly invisible and marginally conductive. In less than perfect no-clean applications, you may have a more visible and more conductive residue (and a sticky finish that attracts dust). This could present a major issue. Besides dust, you also need to be concerned about other environmental attacks on the flux residue such as heat and humidity. This could increase the flux�s conductivity and residual corrosiveness, leading to board failures. You either need very good process control (flux delivery, profile, cleanliness testing, etc) or you can eliminate any flux-caused reliability issues by cleaning the board.
Regards,
Mike Konrad Aqueous Technologies konrad@aqueoustech.com www.aqueoustech.com 909.944.7771 ext 29
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