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 >>> >>>