There are two schools of thought about this. I personally am much in favour of
solder-plugged via holes. As the aspect ratio of hole diameter to laminate thickness is
getting smaller, the throwing power of the plating is not any greater and the quantity
of copper in the hole is decreasing because of this and because the periphery of the
barrel is smaller. The resistance is therefore increasing. Plugging the hole with
solder therefore:
- decreases the resistance
- maintains electrical continuity, even if the copper subsequently fails for any reason

- provides visual indication if barrel cracking occurs (no meniscus on top surface)
- prevents contamination pockets from forming and easing cleaning

Hope this opinion helps

Brian

Kiiski Jarmo wrote:

> I have a question about hand soldering of a wire to solder plugged via.
> Nowadays there is a temporary solder mask (TSM) preventing the soldering of
> these plated through holes at wave soldering machine. After wave soldering
> the TSM is removed and the wire is soldered to hole at assembly. Now I get
> this great idea! What if we just leave the TSM out and let the holes to be
> filled with solder. At assembly the solder will be melted and wire will be
> placed to hole and the solder joint is formed with proper final heating and
> cooling.
>
> What problems or risks can be expected, when doing such soldering? Are the
> joints as reliable as normally? I won't like to remove the solder before
> placing the wire, I would like use it to form the solder joint to save time.
> Would I need some extra soldering wire or flux?
>
> Have a nice weekend
>
> B.R.
> Jarmo Kiiski
> email: [log in to unmask]
>
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