John,
still cap guru? Side question: X7R=pyro/ferroelectric & hysterisis..NPO=none..is that the whole truth? We feel that even NPOs do some tricks...built-in tensions after soldering..CTE mismatch..making stocastic 'pings' when tempcycled. Know Ousten? Ever cooperated with the French?
Regards/
Ingemar Hernefjord
Ericsson Microwave Systems

-----Original Message-----
From: John Maxwell [mailto:[log in to unmask]]
Sent: den 19 juni 2002 02:13
To: [log in to unmask]
Subject: Re: [TN] Wavesoldering Ceramic Caps


Bill,
I kind of wish I was still consulting on cracked capacitors as I would view
this as a great business opportunity. Good luck but I do not believe that
you will ever be successful in wave soldering that case size.

John Maxwell

At 10:30 AM 6/18/02 -0400, you wrote:
>Hello gang,
>
>We have a situation where a board design has some 2225 Ceramic Caps on the
>bottom side of the board. Most of the advisories I've seen indicates that
>wavesoldering these parts is not recommended. From what I can gather,
>thermal shock induces micro fractures within the ceramic substrate that
>leads to component failure. However, I'm thinking that if I could raise my
>normal wave preheat and lower my pot temperature, I could minimize the
>thermal shock. I could almost have a thermal profile that would be similar
>to reflow soldering. Reflow soldering of these ceramic caps, from what I've
>read, is OK. Some of the articles I've read on this cracking phenomenon were
>written in the late 80's, Is there any newer information out there?
>
>Is anyone out there routinely wave soldering these parts that could give me
>some pointers?
>
>We use an OA flux with a DI water wash in our process.
>
>As always your help is greatly appreciated.
>
>Bill Kasprzak
>Moog Inc. Manufacturing Engineering, Electronics
>
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