for high temp?
On Sep 20, 2018, at 10:16 AM, David Hillman wrote:

> 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
>>>>
>>>>