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From:
Douglas Pauls <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, [log in to unmask]
Date:
Wed, 12 Feb 2014 07:36:52 -0600
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Excellent contribution as always Bev.
I cannot find the paper that I was quoting.  I found one that is close, 
"Ionic Cleanliness of LPISM Boards" by Hank Santfleben, who is still at 
Delphi (and a Fellow), from the 1995 time frame.  I can send you that PDF 
if you like. 

Phil retired from Delphi a couple five years ago and I have lost track of 
him. Hank might be able to find the papers I referenced.

Doug Pauls



From:   Bev Christian <[log in to unmask]>
To:     <[log in to unmask]>
Date:   02/11/2014 07:48 PM
Subject:        Re: [TN] Risks Associated with Calcium
Sent by:        TechNet <[log in to unmask]>



All,
This thread has been, well, hilarious, exhilarating and instructive all at
once.  Rich, I thought your "OK then..." was actually one of the funniest
parts. I can just see you saying something like that in an IPC meeting.

But seriously, let's look at this a bit, starting with your list.
#1 CaCl2 from deicing compounds. 
I am certain that Doug said is right - go through your process and find 
out
where the calcium first shows up.

#2 Calcium from factory humidification misters
We had a problem with those in our lab - which crapped out a multi-hundred
thousand dollar x-ray machine by the way.  We had a devil of a time 
tracking
down where the contamination was coming from.  We had to devise a catch
system to capture the aerosol of water droplets being put out by the 
mister,
take samples from various points in the water delivery system and then run
IC on all the samples.  In our case the offending cation was sodium 
although
there were smaller amounts of K, Ca and Mg also present.

#3 Talc from powdered gloves 
Talc is Mg3Si4O10(OH)2 so I doubt this is your source of calcium.

#4 E-glass in the laminate 
E-Glass is a low alkali glass with a typical nominal composition of SiO2
54wt%, Al 2O3 14wt%, CaO+MgO 22wt%, B2O3 10wt% and Na2O+K2O less then 
2wt%.
Where is the Al and Mg?
Again, I doubt this is your source.

#5 filler in the solder mask
Yep, my first guess, IF you are finding it on the surface of virgin boards
right out of the package.

#6 DI water
???
Same situation as #2.


Doug,
You stated:
"Phil Wittmer and some of his colleagues at Delco Electronics (now Delphi)
published papers years ago where they treated cations as process
indicators."
Could you send me the references? 

Rich,
Keep us posted as to the results of your investigation!

Regards,
Bev

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Richard Kraszewski
Sent: Tuesday, February 11, 2014 12:38 PM
To: [log in to unmask]
Subject: Re: [TN] Risks Associated with Calcium

OK then....

Thanks for the replies.  Even the ones that turned this into a more 
surreal
experience than even I typically expect to have on any given workday.

My list of more bland replies (albeit it begrudgingly useful) both on and
off forum include the following:

#1 CaCl2 from deicing compounds. 
#2 Calcium from factory humidification misters
#3 Talc from powdered gloves 
#4 E-glass in the laminate 
#5 filler in the solder mask
#6 DI water 

The above list is useful from a source stand point, however am still
struggling with the effects that could be seen with low levels of Ca (i.e.
<1-2 ugm/inch). I suspect none if any. 

Studies conducted by the Minzari in Denmark suggests that calcium warrants
limited concerns as only Sn, Pb, Cu and Ag present sizable ECM risk. 
(IEEE,
volume 9, Sept 2009).
 
I have a suspicion that any requirements for low levels of calcium on
assemblies have been propagated from those used in the semiconductor
industry. While those may be required in semiconductor world, they may not
have good applicability in the realm of PCA manufacture. 

Any further thoughts on "RISKS" associated with low levels of calcium?

Rich Kraszewski
PLEXUS


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Tuesday, February 11, 2014 9:15 AM
To: [log in to unmask]
Subject: Re: [TN] Risks Associated with Calcium

Hi Steve,

You hit the nail on the head!!

http://www.youtube.com/watch?v=KX9mBaHtTrs


Steve 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steven Creswick
Sent: Tuesday, February 11, 2014 7:22 AM
To: [log in to unmask]
Subject: Re: [TN] Risks Associated with Calcium

Doug,

Don't overlook that which is right in front of your co-ops face!

Please remember that a cow's tongue is long enough, and flexible enough to
reach inside its nostrils and extricate whatever may be resident there.

Certainly, at this time of year there may be significant 'thickening 
agents'
and moisture present.

Just thought you would like to know for testing!


Steve Creswick
Sr Associate - Balanced Enterprise Solutions
http://www.linkedin.com/in/stevencreswick
                         616 834 1883




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