PCB'deki kurşunsuz lehim bağlantılarındaki siyah noktalar nelerdir??

Bir PCB prototipi yapıyorum, using Chip Quik's "SMDSWLF.031, Sn96.5/ Ag3.0/ Cu0.5 lehim 2.2% temiz olmayan akı. I find that the black spots appears frequently in larger pads on my board. I wonder if it is because I left the soldering iron more time heating the solder and that burnt the flux. What is that black residue? Is that a sign of a bad joint or maybe bad soldering technique?

PCB Montajı, PCB Tasarımı
Aralık 1, 2023

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.

Devamını oku: PCB Prototipi

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Oliver Smith

Oliver, PCB tasarımı konusunda yetenekli deneyimli bir elektronik mühendisidir, analog devreler, gömülü sistemler, ve prototipleme. Derin bilgisi şematik yakalamaya kadar uzanıyor, cihaz yazılımı kodlaması, simülasyon, Yerleşim, test yapmak, ve sorun giderme. Oliver, elektrik tasarımı yeteneklerini ve mekanik yeteneğini kullanarak projeleri konsept aşamasından seri üretime geçirme konusunda uzmandır.

Oliver Smith

Başkaları Ne Soruyor?

Do you allow your manufacturer to do some changes to your PCB design?

I receive an email from My PCBA suppliers. They advised us to adjust our original PCB design. Are there any PCB designer have this experience after releasing original design to your supplier? Eğer evetse, do you think that the manufacturer can make your design better?

Oliver Smith Eylül 19, 2023