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*

400 Collins Road NE, MS 108-101, Cedar Rapids, IA  52498  USA

*Tel:* +1 319 295 2109 | *Mobile: *+1 319 431 3773

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On Fri, Jan 3, 2020 at 3:45 PM David Hillman <
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> 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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