Peter,
no, they are normally not coated, but I think it is a solution to save them.
(we have a coating process installed in our facilities)
Marie
> -----Original Message-----
> From: [log in to unmask] [mailto:[log in to unmask]]
> Sent: mardi, 14. janvier 2003 10:34
> To: [log in to unmask]
> Cc: [log in to unmask]
> Subject: Re: [TN] voids in gold plated holes
>
>
>
> Marie,
>
> Are your boards to be conformally coated? If you're worried
> about exposed
> copper, you could try filling the holes with dilute conformal
> coating -
> though you will probably have to put the boards in a vacuum
> oven to pull
> the air out of the holes and allow the coating to penetrate
> and coat the
> walls of the holes.
>
> Peter
>
>
>
> ME Magnin <[log in to unmask]> 14/01/2003 04:02 PM
> Sent by: TechNet <[log in to unmask]>
>
> Please respond to me.magnin
>
>
> To: [log in to unmask]
>
> cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST
> Aero/ST Group)
> Subject: Re: [TN] voids in gold plated holes
>
>
>
>
>
>
>
>
>
>
>
>
> Thanks for this answer and all the others
> I was not sure, when reading IPC A600 3.3.9, that it was talking about
> copper voids or all plating voids. I understand now that the
> last is the
> correct understanding.
> I can see exposed red copper in these voids, I suppose there
> has been a
> problem during nickel plating, thus consequently gold is missing too.
> The number of voids is close to the acceptance limits,
> depending on the
> standard I base on (IPC or PERFAG).
> But my major concern is that the boards are finished now, and
> I am not sure
> I can deliver them like this : bare copper is still exposed
> because I have
> had poor vertical fill (we use a no-clean solder flux).
>
>
>
> ME Magnin
>
> FIRSTEC SA
> Rue du Grand Pr¨¦ 70
> CH 1211 Gen¨¨ve 2
>
>
> T¨¦l. : +41(0)22 918 36 85
> Fax : +41(0)22 918 36 93
> mailto:[log in to unmask]
> http://www.firstec.ch
>
>
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]]On Behalf Of [log in to unmask]
> Sent: lundi, 13. janvier 2003 20:58
> To: [log in to unmask]
> Subject: Re: [TN] voids in gold plated holes
>
> Marie
> If you look in IPC-6012A, para 3.3.3 There is a table 3.3
> that has the
> requirements for Finish Coating. Then depending upon which
> class your
> product has been built to meet, you can see the
> requirements. Class 2
> says "Three voids allowed per hole in not more than 5% of
> the holes" for
> example.
>
> Bare copper is always a reliability concern - especially if it is in
> contact with gold. Remember that the nickel is put on to
> prevent the gold
> and copper from reacting.
>
> Susan Mansilla
> Robisan Lab ---------------------------------------------------
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