Hi Richard,

Did some work for Schlumberger back when I was in Tulsa. We had a dual pot
Technical devices wave machine with one of the pots filled with HMP solder.
I didn't know how the boards were able to withstand going across a wave of
300 C. liquidus solder but they did. I got to see one of the tools and how
these boards are mounted in the tools, they're all potted with a 1-inch
thick layer of potting material around the assembly inside a cavity
machined into the tool. Like you said, you don't even want to think about
failure. With all the horizontal drilling that they do nowadays there can
be thousands and thousands of feet of pipe in the well that will need to be
pulled to get to the tool at the end of the pipe if you need to fix
something.

Steve

On Thu, Sep 20, 2018 at 11:00 AM Stadem, Richard D <[log in to unmask]>
wrote:

> Yeah, and no MEMs or BTCs would ever be allowed, either!
> Hmm.....maybe we should go back to those old rules, LOL!
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of David Hillman
> Sent: Thursday, September 20, 2018 9:17 AM
> To: [log in to unmask]
> Subject: Re: [TN] High Temp SnPb solder
>
> LOL - if we were following the old rules then there would not be a
> component called a BGA.............. :-)
>
> Dave
>
> On Thu, Sep 20, 2018 at 9:07 AM, Yuan-chia Joyce Koo <[log in to unmask]>
> wrote:
>
> > according  to my book (old), you should NOT count  on solder as
> > mechanical  support of ANY kind.  solder is intended to  provide
> electrical
> > connect, use solder, especially high temp  solder (assume you are going
> to
> > use it at elevated temp for service, or assembly sequence - such as
> > multiple reflows... it is difficult to count  on microstructure to be the
> > same as you initially put down).
> > as for FEM purpose, I would use 50% book  value that tell you  - if i
> > were you...
> > my 1.5 cents.
> > jk
> > On Sep 20, 2018, at 9:54 AM, Stadem, Richard D wrote:
> >
> > Adding to what Dave said; you don't get something for nothing! Different
> >> alloys have different physical characteristics and are used for
> >> correspondingly different purposes and applications. Don't attempt to
> use
> >> something not AABUS and fully documented on the applicable BOM.
> >>
> >> -----Original Message-----
> >> From: TechNet [mailto:[log in to unmask]] On Behalf Of David Hillman
> >> Sent: Thursday, September 20, 2018 6:57 AM
> >> To: [log in to unmask]
> >> Subject: Re: [TN] High Temp SnPb solder
> >>
> >> Hi Ben - yes, there are differences in the mechanical properties and the
> >> solder joint microstructures for the "high temp" alloys. Most of those
> >> alloys have applications in component construction, specifically in
> >> component die attachment. One very common alloy used frequently in a
> >> number
> >> of applications is the 10Sn88Pb2Ag alloy.
> >>
> >> Dave Hillman
> >> Rockwell Collins
> >> [log in to unmask]
> >>
> >> On Thu, Sep 20, 2018 at 6:40 AM, Gumpert, Ben <[log in to unmask]>
> >> wrote:
> >>
> >> TechNetters,
> >>>
> >>> J-STD-006 has a series of 'high temp' SnPb alloys (some with Ag) that
> are
> >>> close in SOL/LIQ temps. I'm familiar with Sn10Pb90 as a common
> high-temp
> >>> ball on ceramic BGAs, but I haven't seen the others used. Are there any
> >>> differences (e.g. mechanical properties) among these that would drive
> >>> selection, other than the SOL/LIQ?
> >>> Are some alloys more readily available than others?
> >>>
> >>> Ben
> >>>
> >>>
>


-- 
Steve Gregory
Kimco Design and Manufacturing
Process Engineer
(208) 322-0500 Ext. -3133

-- 



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