Yes the solderjoint should be strongest so tests like this go to destruction anywhere but
the solder joint if it is good and the test is done to stress sheer or tensile strength.
However solder joints have low peel strength so you must set up your jig alignment to
consistently avoid peel or you will get [variable] low numbers. The rate at which you
stress should be consistent also. At the very small numbers you are looking for there is
little practical
difference between tensile and shear strengths,so unless you have nail headed pieces of
wire the easiest test to perform is shear so I suggest you go for that.

What is your customer' concern, maybe you can address it some other way if you are unhappy
or unable to do this test. [I guess he's worried about gold embrittled joints].

Mike Fenner
Bonding Services & Products
T: +44 1295 722992
F: +44 1295 720937


----- Original Message -----
From: Severson, Scott M. <[log in to unmask]>
To: <[log in to unmask]>
Sent: 13 October 1999 22:11
Subject: Re: [TN] Pull Strength Value


> Don,
>
> In my opinion pull strength is a very poor measure of reliability.  I don't
> know off hand what the "pull strength" should be, however if the failure
> occurs anywhere except at the interface between solder and lead (fracture
> through bulk solder, wire tensile break, or pad pull off) the solder joint
> is as good as it can be.
>
> A micro-section of the joint is a better indication of the joint quality.
> Hope this helps.
>
> Scott M. Severson
> Benchmark Electronics Inc. - Winona
>
> -----Original Message-----
> From: Steffen, Don E [mailto:[log in to unmask]]
> Sent: Wednesday, October 13, 1999 2:58 PM
> To: [log in to unmask]
> Subject: [TN] Pull Strength Value
>
>
> Techno's
>
> I have an anomaly that I wonder if anyone out there can help me with. My
> customer is asking me to come up with a Pull Strength value. The discription
> of the anomaly is that I have a 42 gauge, Copper ciol wire that is hand
> soldered to a gold plated terminal. I need to quantify the strength of the
> solder bond of the 42 gauge wire that is soldered to the gold lead. I want
> to due a pull test of the wire with a Chillion Pull gage. Does anyone out
> there know what the value that is considered to pull a wire away from
> solder? How is this test performed?
>
> Senior Quality Engineer
> VDO Control Systems
> Auburn, IN 46706
> Phone (219)925-8887
> Fax (219)925-8710
> Email: [log in to unmask]
>

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