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March 2015

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Subject:
From:
Wayne Thayer <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Wayne Thayer <[log in to unmask]>
Date:
Mon, 30 Mar 2015 13:30:13 +0000
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I can't agree that "Plate thru hole solder joints are truly indestructible."

Solder is a strange material to use for mechanical connection. As a metal, it 
is pretty weak under the best of circumstances. Depending on temperature and 
rate of stress, it is EXTREMELY weak. Years ago we had a mechanical engineer 
who used a through-hole solder joint to maintain stress on a spring. Held for 
about a year! I suggest you repeat that experiment, with the through hole 
solder joint suspending a weight about 600mm above your keyboard and let us 
know how long it lasts!

But we all design modules which depend on the solder as a mechanical 
connection. As long as the time constant of the stress is low enough (shock 
loads, diurnal temperature stress, etc.), it works pretty well when compared 
with organic adhesives (until grain growth and cyclic fatigue do their work).

Wayne Thayer

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of David Hillman
Sent: Monday, March 30, 2015 8:47 AM
To: [log in to unmask]
Subject: Re: [TN] Leaded component, lead pull test

Hi Victor - not much data in the public domain on that topic. About the best 
you can do is get a copy of the International Tin Research Institute's 
Publication 656 titled "Solder Alloy Data". Publication 565 contains tensile, 
fatigue and shear data for a number of solder alloys over various temperature 
and stress/strain rates. The testing we completed back in the early 1990's at 
Rockwell Collins on plated thru hole strength nearly always resulted in 
failure of the plated thru hole/laminate rather than the solder joint itself 
using slow tensile speeds (unpublished). Plate thru hole solder joints are 
truly indestructable.

Dave Hillman
Rockwell Collins
[log in to unmask]

On Fri, Mar 27, 2015 at 3:10 PM, Victor Hernandez < 
[log in to unmask]> wrote:

> Fellow TechNetters;
>
>    Does anyone have information on the following:
>                Finish hole size, lead diameter, solder type, thickness of
> board and lead length.   How much force does it require to pull out a lead
> from the solder joint.   Will the lead come out cleanly or elongated and
> snap,
>
> Victor,
>
>
> ______________________________________________________________________
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