A shorter time than it takes to conduct an SIR test....................

Dave

On Fri, Jan 3, 2020 at 3:49 PM Douglas Pauls <
[log in to unmask]> wrote:

> Ya gotta wonder how long it takes to plate up 15 INCHES of gold......
>
> *Douglas Pauls *| Principal Materials and Process Engr | Advanced
> Operations Engineering
>
> *COLLINS AEROSPACE*
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> On Fri, Jan 3, 2020 at 3:45 PM David Hillman <
> [log in to unmask]> wrote:
>
> > Hi Murray - if you can get a true ENIG plating chemistry to put 15
> > inches of gold thickness on a board, you would never want to use the
> board
> > as the gold plating would have severe structure and/or solderability
> > issues. The IPC-4552 specification contains the industry consensus gold
> > plating thickness range that applies to producing an acceptable and
> > reliable ENIG plating layer. Any gold plating thickness outside of that
> > range would be questionable at best for quality and reliability unless
> you
> > are working closely with a plating chemistry supplier who is doing a
> custom
> > plating bath composition. One of the early issues of ENIG plating was the
> > industry asking the plating chemistry suppliers to provide an immersion
> > gold plating thickness that exceeded the acceptable physics of the
> plating
> > chemistry (basically this is how we discovered "black pad"!).
> >
> > Dave Hillman
> > Collins Aerospace
> > [log in to unmask]
> >
> > On Fri, Jan 3, 2020 at 3:30 PM Campbell, Murray <
> [log in to unmask]>
> > wrote:
> >
> > > Happy New Year All,
> > >
> > > Is there any good reason to call out a maximum gold thickness / nickel
> > > thickness on fab notes or is it sufficient to rely on simply stating
> that
> > > the fabricator shall follow ipc-4552 minimum thickness?  I have seen
> some
> > > companies state that a maximum thickness upwards of 15 µin to be
> > > acceptable.  Is there any value in stating an upper range?
> > > I know it states in 4552 that an upper range had been debated and not
> > > necessary but I still see an upper added to fab notes.
> > >
> > > Regards,
> > >
> > > Murray Campbell
> > > PCB Design Specialist
> > > [log in to unmask]<mailto:[log in to unmask]>
> > > [cid:[log in to unmask]]
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