Tim Stammely asked:

>Where should I place my thermocouples to determine the best oven profile
>for assemblies having BGAs since their leads aren't reachable, and how
>should I attach them?

You must scrap a product to do this, but one way is to drill hole(s) from
the opposite side of the board into the collapsed "ball" joint of an
assembly, fill the hole with thermal epoxy, and insert the thermocouple
into the hole.

Of course, it may be extreme to think that it is a necessity to know the
exact temperature of that solder joint - as any known position on the board
which can be expected to react to the thermal cycling might be used to
establish a profile. But if you wish to measure the joint temperature very
closely, I'm unaware of a better way...


regards,


Jerry Cupples
Interphase Corporation
Dallas, TX USA (not "titletown" but you can forget Green Bay, too)
http://www.iphase.com

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