why you need max min? if you need for reliability reason using Pb
rich solder to relief some strain for example, you will need to have
preform to define min. thickness. Unless your design is pushed to
the limit - extreme temp included, or try to fix someone's crappy
design at late stage, you don't use that... you will need (1)
process control data, (2) FEM for thermal expansion analysis for
example, etc.- not difficult if only a bit off, but it would very
difficult if it is way off the mark (like someone selected a low Tg,
high CTE board to cut cost... scream bloody murder...).
On Aug 29, 2016, at 4:12 PM, Decker, Scott UTAS wrote:
> For some reason, I thought I saw a spec that mentioned what the
> minimum and maximum solder thicknesses are or can be between the
> component termination and the board pad. I looked through the J-
> Standard for soldering and could only find a reference to Dimension
> "G" note 3 which reads "Must show evidence of wetting." but no
> minimum or maximum. Can someone point me to the spec if there is
> one, for this soldering aspect of an assembly, or tell me I'm
> seeing things that don't exist... Thanks in advance...
> Happy Monday to all!
>
> Scott Decker - Senior Analyst, Drafting & Design Services CID+ -
> Electronic Systems Center
> UTC AEROSPACE SYSTEMS
> 3445 S. 5th Street, Suite 170, Phoenix, AZ 85040 U.S.A.
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