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From:
Bev Christian <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Bev Christian <[log in to unmask]>
Date:
Wed, 12 Mar 2014 21:20:39 -0400
Content-Type:
text/plain
Parts/Attachments:
text/plain (101 lines)
When I was at Nortel in the 1990s we developed "standard" expected pull and
shear values for common SMT components using a Dage device.  Another Nortel
site did the same thing using an Instron. Guess what? The compared results
were within the range of standard deviations we developed from the data.
But other than telling you if you have the potential for a gross failure,
what does this data give you?  Not much.
Bev

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Wenger, George M.
[Contractor]
Sent: Wednesday, March 12, 2014 8:56 PM
To: [log in to unmask]
Subject: [TN] FW: Solder Joint Interconnect Pull Strength Tests - Standards?

Steve,

I responded to Todd's TN post off-line but then realized that there might be
others at TN who might want to see what I sent Todd.  I've attached a PDF
file with the info in case you'll be able to put it up on your site.

Regards,
George
George M. Wenger
Failure Signature & Characterization Lab LLC
609 Cokesbury Road, High Bridge, NJ 08829
(908) 638-8771 Home  (732) 309-8964 Mobile
E-mail [log in to unmask]
[log in to unmask]


-----Original Message-----
From: Wenger, George M. [Contractor] 
Sent: Wednesday, March 12, 2014 1:01 PM
To: 'MacFadden, Todd'
Subject: RE: Solder Joint Interconnect Pull Strength Tests - Standards?

Hi Todd,

I'm not sure that this is what you are looking for.  There really isn't any
recognized industrial pull strength specifications.  The attached shows what
we did many years ago when we first started seeing what we called "Double
Reflow" defects.  At that time we found that typical 50 mil pitch gull wing
lead solder joints had a pull strength of approximately 1Kg force (2.2 lbms)
when pulled at room temperature and the pull strength decreased linearly
with temperature.  When we did pull strength testing we were much more
interested in the mode of failure rather than the strength.  We always
wanted to see cohesive failures in the solder and not adhesive failures at
an interface.  I hope you get some usefull information from the attached. 

Regards,
George
George M. Wenger
Failure Signature & Characterization Lab LLC
609 Cokesbury Road, High Bridge, NJ 08829
(908) 638-8771 Home  (732) 309-8964 Mobile E-mail [log in to unmask]
[log in to unmask]


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of MacFadden, Todd
Sent: Wednesday, March 12, 2014 12:04 PM
To: [log in to unmask]
Subject: [TN] Solder Joint Interconnect Pull Strength Tests - Standards?

Is anyone aware of standards for conducting and evaluating lead pull tests,
and are there typical expected lead pull (or push) values for the common
interconnects (i.e., gull wing, castellation, BGA, chip cap terminals, etc).

Perhaps there are too many variables -- e.g., type, finish, configuration
and size of the lead; solder type, etc. -- to establish standard pull
strength values. We've always just used relative comparison of values from
sample lots against controls, but I'm wondering if there are typical
expected pull strength values from industry we can reference.

I noted from MIL-STD-1580B: 10.1.1.2 Terminal strength. Perform a lead pull
strength test on all parts (two parts minimum) in accordance with the
applicable specification. But what is the "applicable specification" being
referred to here?


Thanks in advance!
Todd MacFadden


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