Thanks Dean,
Nothing like people making up terms and abbreviations willy-nilly as they go along to bring clarity to issues.
Therefore, Dale did not give us any information as to what components he is talking about.
Werner
-----Original Message-----
From: Stadem, Richard D. <[log in to unmask]>
To: TechNet E-Mail Forum <[log in to unmask]>; Werner Engelmaier <[log in to unmask]>
Sent: Tue, Jul 20, 2010 12:12 pm
Subject: RE: [TN] solder joint height
Hi, Werner
The military customers insist on us using the term CCA for Circuit Card
Assemblies. This is the populated, finished circuit board level assembly, not
the bare board (PWB) or captive device CCCA in the built-up box.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier
Sent: Tuesday, July 20, 2010 10:19 AM
To: [log in to unmask]
Subject: Re: [TN] solder joint height
Hi Dale,
Do you mean CGA's [column grid arrays]? If not, what do you mean by cca?
610, Class 3 or otherwise, only addresses quality, not reliability—for that you
need to go to IPC-D-279.
While the absence of solder fillets can reduce fatigue life, the presence of
fillets, 'robust' or otherwise, does not have any positive first-order impact.
However, solder joint height does.
You may be looking at IMC crystals.
Werner
-----Original Message-----
From: Hart, Dale L CTR USAF AFMC AFRL/RXSA <[log in to unmask]>
To: [log in to unmask]
Sent: Tue, Jul 20, 2010 9:23 am
Subject: [TN] solder joint height
We have been doing a some analysis of cca's for the Air Force consisting of
SMT. The visual inspection of the solder joints looks very good all
characteristics above the suggest minimum for class 3 of 610. The solder
fillets in some instances could be characterized as being robust. In
cross-sectional analysis however, the solder joint height of the components
electrical termination above the land has been perhaps 0.025 mm to the point
of needing a SEM to look at the land-solder-component lead interface.
Closer examination in these areas revealed small cracks in the grain
boundaries. I used the term grain boundaries because the solder in these
areas do not resemble the colonies observed in the bulk solder of the
fillet. In some of these instances the land is often deformed in the shape
of the component lead.
Would these joints although stronger be more susceptible to fatigue or
overload failure?
What are the implications if these cca's are encapsulated?
What suggestions could be offered to the manufacturer?
Dale L. Hart
Universal Technology Corporation (UTC)
Failure Analysis
1270 North Fairfield Road
Dayton, Ohio 45432-2600
(937) 656-9165
Fax (937) 656-4600
Email: <mailto:[log in to unmask]> [log in to unmask]
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