Those dark splotches may be leftovers from the resin-based flux. No-clean fluxes are often made out of water-soluble resins (vs rosin) and during heating, most of it will evaporate away.
Pay attention to soldering temperatures. Sn96.5/Ag3.0/Cu0.5 solder’s liquidus is 217 ° C. Soldering at high temperatures you have been using can potentially damage components, has been weakening the glue under every pad you solder (the copper is glued to the FR4), producing significantly more hazardous fumes, something that is already more hazardous with lead-free solders, and generally does nothing good.
As far as I know, it should not have a meaningful impact on the joint, but if you want to avoid this, I suggest lowering your iron temperature (and possibly getting a new tip and/or iron depending, so soldering is effective at said lower temperature), though this may not totally resolve the issue.
Lees verder: PCB-prototype
#PCB Assembly #PCB Design
Bringing your electronic ideas to life begins with PCB drawing, which is the process of…
Printed Circuit Board design is one of the most significant processes in electronics production. Deciding…
De elektronische apparaten die we gebruiken, veranderen en worden voortdurend geüpgraded. Ze worden kleiner en functioneler,…
PCB-assemblage is een zeer gecompliceerd proces, waarbij nauwkeurigheid altijd van essentieel belang is. Even…
Het is belangrijk om ervoor te zorgen dat een PCB-ontwerp betrouwbaar is, omdat er geen ontwerpfout is gemaakt,…
Tijdens het ontwerpen van de printplaat, a high level of concentration is given towards PCB signal…