Although lead free HASL (LFH) has some issues to overcome to modify its tarnished reputation urgently, this not so popular surface finish is consistently gaining popularity amongst customers making manufacturers give it a second look as a main staple up against immersion silver, OSP, and immersion tin. But why? In this article, we’ll say something about LFH.
Actually, LFH needs to be applied at a hotter temperature. On the first pass the surface is left grainy and dull. Once a second pass is added the surface and appearance improves to a shiny, much flatter, and smoother even coat.
After a lot of changes to chemistries and processes lead free HASL is now a stable surface application to use on PCBs. This longtime reliable surface finish is still used today in military, aerospace, medical, and other applications.
ENIG, OSP and even immersion tin and silver all took the lead in manufacturing while lead free HASL was still a process headache. However, as technology develops and continues to do so, real estate on surface becomes tighter and foot prints decrease, it is clear LFH still can prove itself to be a winner.
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