Pete

It is more likely that your supplier had a brightner control issue. The T.&
E. is usually run once a month. The brightner could have been out of control
for a very limited amount of time affecting a limited number of lots. The 6
X 550 degrees thermal shock test is a highly effective way of detecting
plating issues. A large percentage of our customers rely on it. That way
every lot is tested.

Bob Whitehouse


-----Original Message-----
From: Menuez, Pete [mailto:[log in to unmask]]
Sent: Monday, June 20, 2005 11:10 AM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] Grain Structure

All:

The T&E's run during this period were in the 30%/45K range. (I've been told
that the ASF for the coupons was the same as normal production.)

Based on this information and the failures, I am concluding that the grain
structure inside the holes is different than the grain structure on a flat
piece of stainless steel; thus my grain structure evaluation suggestion.

Pete





-----Original Message-----
From: Ronnie Walker [mailto:[log in to unmask]]
Sent: Monday, June 20, 2005 10:10 AM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] Grain Structure




In my mind, that issued should be picked up in process control measures
like T & E of the copper bath, thermal shocks of the bath, thermal shocks
of the procuct and chemical process control..
I do not understand how you received boards with such a condition.



                      "Menuez, Pete"
                      <Pete.Menuez@L-3C        To:
[log in to unmask]
                      OM.COM>                  cc:
                      Sent by:                 Subject:  [IPC-600-6012]
Grain Structure
                      IPC-600-6012
                      <IPC-600-6012@ipc
                      .org>


                      06/20/2005 08:44
                      AM
                      Please respond to
                      "(Combined Forum
                      of D-33a and
                      7-31a
                      Subcommittees)"






All:

We are currently completing an investigation of some bare board failures
and found the cause to be poor grain structure of the plated through holes.
The plating is columnar which provides weaker copper and eventually plating
cracks throughout the holes.  Our testing showed 100% failure of this lot
after thermal stress.

Has there been any discussion in this group regarding adding grain
structure as inspection criteria?  Does anyone know of any references or
standards regarding grain structure? I have talked with several of our
suppliers and some of them have commented back that they don't have a good
reference to good/bad plating grain structure.

If you would like to see a report with pictures email me with your address
and I'll send the report to you.

Pete



Pete Menuez
Supplier Quality Engineer
L-3 Communications Cincinnati Electronics
7500 Innovation Way
Mason, Ohio 45040
[log in to unmask]

513-573-6401 Voice
513-573-6767 Fax

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