leaded or unleaded?

Soldering iron or hot air?

How skilled are the techs?

/129 will handle a bunch of manual leaded rework, I'd worry about lead free.  Especially if the techs aren't skilled, or are impatient and use too much heat.  I've never been a big fan of the slash sheets.  I think they can be ambiguous and restrictive at the same time, and don't really reflect the laminates being manufactured.  If you do need to specify material to take this abuse, specify what parameters are important.  Peel strength would be important.  Repeated heat cycles break down things like CAF resistance, Z-Axis expansion, Tg.  So you may need to spec things like non-dicy, different Z-Axis measurement procedures.  And oddly enough, after a few cycles, some 170+ Tg materials end up with a lower Tg than materials that started at 140.

I'm not sure I answered your question or created more.  My only actual answer is that slash sheets might not be good enough for this situation.

The designer in me says address the root.  Regardless of PCB material, those multiple cycles cost money and increase risk.  If it was only happening in development, let it go.  If it's expected to continue for production, look into it.

Pete

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