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March 2000

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From:
"Ingemar Hernefjord (EMW)" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Fri, 24 Mar 2000 08:32:05 +0100
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Real good pages, Steve, to be an oldie, you are very alert. David, I know a guy who has been simulating and calculating soldering of caps and like for years. Maybe, he is not willing to tell everything, but you can at least try. I send his adress offline, he has little time to act as a world oracle. Anyway, we have cooperation with Kemet, AVX, Kyocera, Murata etc, and we have learnt that the geometry of the solder joint is of crucial importance. We have extremly large boards in some applications, with metal back and Teflon. Mounting ceramic caps on such boards is seemingly crazy, but works well since many years. Another guy you can contact if you want deeper knowhow about the stress mechanisms is prof. Akay in Indiana. He has a whole group busy with your things. <[log in to unmask]>.
Good Luck
Ingemar Hernefjord

-----Original Message-----
From: Stephen R. Gregory [mailto:[log in to unmask]]
Sent: den 23 mars 2000 21:27
To: [log in to unmask]
Subject: Re: [TN] Ceramic Capacitor Strength Versus Size


In a message dated 03/23/2000 2:05:18 PM Central Standard Time,
[log in to unmask] writes:

<< I have been battling SMT ceramic capacitor cracking problems for a while,
as
 I am sure most of you have.  I am experiencing cracking from mechanical and
 most likely thermal stress as well.  I have addressed many of these issues
 (depanelization, profile, etc...) using literature from MLC manufacturer's
 technical information.  I am now looking for a general capacitor size vs.
 strength data for various stresses.  I know that generally larger parts are
 more likely to have problems but for each size of cap it is difficult to
 compare.  I have looked at RAC data as well as IPC, and have not found
 anything exactly like what I am looking for.

 Does anyone know of a source of such information or the best place to start
 compiling a list of my own?

 Any suggestions would be appreciated.

 Thanks

 David Romero >>

Hi David!

Have you been to the AVX website yet? They've got a couple of good *.PDF
articles that gives some good info about zero defect assembly with
multi-layer capacitors. The URL's are:

http://www.avxcorp.com/docs/techinfo/!smtinfo.pdf
http://www.avxcorp.com/docs/techinfo/smzero.pdf

-Steve Gregory-

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