Possibly, it could well be how they do it.
But would the developer work through the tiny holes fast enough? You have
like 1.5mm of soldermask there after all.
Maybe it's soft enough, or they use a forceful spray developer, or both.
I don't see another way really. I do know they use a curtain-coating machine
(where the liquid soldermask is like a waterfall and the boards travel
underneath).
ST
On Mon, Oct 13, 2008 at 12:19 PM, trevwhite74 <
trevor.white100@...> wrote:
>
> > There also seems to be photo-process liquid resist but i do not know how
> > they prevent it from filling the holes. You could drill after, but
> that is
> > not an option for a commercial setup with PTH.
> >
>
>
> I just thought about this. You mask the areas that you want to remove.
> So all the pads are masked off. Then you expose it to UV. Then you
> clean it and all the areas that were masked wash away. So all the
> stuff in the holes will simply wash away as well. I think that is the
> way it would work.
>
> Trev
>
>
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