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February 2014

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Subject:
From:
Phil Bavaro <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, [log in to unmask]
Date:
Tue, 18 Feb 2014 19:55:56 +0000
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Dean,

No, I agree with you completely.   I just don't see the specification addressing component level.   I would like to see the words "component level" added so that everyone sees it the way we do.

In my case, the pre-tinned component may be shipped back to me and sit in stock for a year before it is assembled onto a PWA which is subsequently tested for cleanliness.

Phil

-----Original Message-----
From: Stadem, Richard D. [mailto:[log in to unmask]] 
Sent: Tuesday, February 18, 2014 9:00 AM
To: TechNet E-Mail Forum; Bavaro, Phillip @ MWG - TW
Subject: RE: Cleanliness testing at component level

For me, the difference between components and assemblies is becoming so blurred that it is very difficult to determine where the spec applies and where it doesn't.
Can you tell me that a PoP component consisting of 4 stacked miniature pwbs that is soldered together using a special flux and laser as well as standard solder and flux and touched up and cleaned in an in-line cleaner does not require the same treatment by the specification as the 36" by 24" supercomputer CCA that has 24 layers, 36 miles of copper traces, weighs 45 lbs when populated with just 24 sockets?
Why?

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Phil Bavaro
Sent: Tuesday, February 18, 2014 10:31 AM
To: [log in to unmask]
Subject: [TN] Cleanliness testing at component level

I have reviewed the J-STD-001 several times but still have a question regarding a subcontractor who performs component level soldering operations for Class 3 hardware.


If the subcontractor is performing a soldering operation, then cleaning is required to remove flux residues (this is not  a no clean flux situation).

If the subcontractor is cleaning, then cleanliness testing is required.

The J-STD-001 does not really address the component level when it comes to the Post Soldering Cleanliness Designator (PSCD).

If a component is having its leads pre-tinned or a BGA being re-balled, then is it defaulted to a C-22 PSCD?

My position is yes but I can see where there might be arguments against this since the designator codes seem to speak to the assembly level and not the component level.

My concern is that there is considerable time lag between when component soldering operations are performed relative to the actual PWA process which does get checked for cleanliness.

Any input is appreciated.
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