I wonder what diameter of solder is most useful to demonstrate the property within two or three hours, and with what weight?
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of George Wenger
Sent: Tuesday, November 14, 2017 4:42 PM
To: [log in to unmask]
Subject: Re: [TN] Question on Loading Solder Joints
I'm about to go out to dinner with my youngest son and my two youngest grandsons otherwise I would be downstairs in my work shop hanging weights. What I would like to do is hang three solder wires (1ft, 2ft, and 3ft) and time the creep elongation for each. I'm pretty sure the weight used by the teacher was a 1Kg weight.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of David Hillman
Sent: Tuesday, November 14, 2017 5:37 PM
To: [log in to unmask]
Subject: Re: [TN] Question on Loading Solder Joints
LOL - I have the "test" in progress in my office right now - but the solder wire length is one one foot long!
Dave
On Tue, Nov 14, 2017 at 4:31 PM, George Wenger <[log in to unmask]>
wrote:
> Richard,
>
> Although I have a good analytical mind and remember this demonstration
> very well I may have not gotten the dimension exact. The more I think
> about it I think the blackboard was 4 ft tall and the solder wire may
> have only been 2.5 to 3 ft long and the class was all morning
> (9:00am-11:30) so the solder wire broke before the class was over so
> it might have broken closer to two hours then one hour. Nevertheless, the demo made its point.
>
> George
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D
> Sent: Tuesday, November 14, 2017 5:21 PM
> To: [log in to unmask]
> Subject: Re: [TN] Question on Loading Solder Joints
>
> I can just hear Bev cutting the 4 ft section of wire solder as I write
> this.......LOL!
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of BEV CHRISTIAN
> Sent: Tuesday, November 14, 2017 3:37 PM
> To: [log in to unmask]
> Subject: Re: [TN] Question on Loading Solder Joints
>
> George, Ioan and Dave.
> Thx!
>
> Regards,
> Bev
>
> Sent from Mail for Windows 10
>
> From: George Wenger
> Sent: Tuesday, November 14, 2017 4:00 PM
> To: 'Bev Christian'
> Cc: 'TechNet E-Mail Forum'; 'David Hillman'
> Subject: RE: [TN] Question on Loading Solder Joints
>
> Bev,
>
> I'm really an old timer with lots of practical experience and I can
> remember back in the early 70's taking a class at The Western Electric
> Corporate Education Center in Hopewell NJ and the teach said that you
> should never have a solder joint under a tensile load. He continued
> to say that rather than give you a 1000 words to tell you why not that
> he would show us a very simple and very graphic demonstration. He
> pulled a roll of solid solder wire out of his desk and said it was
> Sn60 but it really didn't matter what the solder alloy was. He cut
> off a 4 foot length of the solder wire and tied one end to a hook at
> the top of the blackboard and then tied a weight to the other end of
> solder wire. He took a chalk and marked a line on the blackboard just
> where the bottom of the weight was. He then continued teaching the
> days lesson but every 15 minutes of class, without saying anything, he
> would take the chalk and mark where the bottom of the weight was.
> After about a little over an hour, while he was busy instructing us on
> the days lesson, we heard a loud "bang". The solder wire had
> continued to elongate while it was under the tensile load of the
> weight and finally the solder wire broke approximately in the middle and the weight dropped onto the floor. Right after every one heard the loud "bang'
> of the weight hitting the floor he stopped what he was talking about
> and simply said "that is why you never what a solder joint to be
> subjected to a continuous tensile load". Although it's been almost 45
> years since I attended that class I'll never forget what he said.
>
> George
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of David Hillman
> Sent: Tuesday, November 14, 2017 3:33 PM
> To: [log in to unmask]
> Subject: Re: [TN] Question on Loading Solder Joints
>
> Hi Bev - I would point them to RJ Klein Wassink's book "Soldering In
> Electronics", ISBN 0-901150-24. In the Mechanical Properties Section
> 8.4 it states "From the data in section 4.7.2 it is obvious that a
> normal soldered connection on a printed board is not well suited to
> withstanding a permanent mechanical load."
>
> And in Section 4.7.2 Creep, there is some good data on the creep
> properties of solder backing up that statement.
>
> Dave Hillman
> Rockwell Collins
> [log in to unmask]
>
> On Tue, Nov 14, 2017 at 2:12 PM, BEV CHRISTIAN
> <[log in to unmask]
> >
> wrote:
>
> > TechNetters,
> > A fellow ex-BlackBerry employee sent me the following query. I
> > obviously no longer have access ot the search capabilities I had at
> > BB. Can anyone offer any suggestions for papers that will meet his
> > needs? I mean I know the reason why, but he wants a paper that
> > proves
> it.
> >
> > I need help with locating a couple of good papers and research
> > studies that explain why designs that place a constant tensile or
> > shear load on board connectors(USB, HDMI, RCA, AC inlet etc.) are a
> > bad idea. Can you point me to a couple of papers on this ? Thanks.
> >
> > Regards,
> > Bev
> >
> > Sent from Mail for Windows 10
> >
>
|
