I really dislike the term "activation", it's misleading.

The activators used in "no-clean" fluxes (and Dave Hillman really prefers
"low-solids") are typically dicarboxylic acids that will volatilize at
soldering temperatures, so several seconds at 220-260C usually drives off
enough dicarboxylic acid that the flux residue remaining on the board is
relatively safe with respect to electrochemical failure modes in most
service environments.  The amount of time at a certain temperature depends
on the particular flux being used.  However , the flux residue is not the
only things on boards that can have a deleterious effect on reliability.

Karen Tellefsen - Electrical Testing
[log in to unmask]
908-791-3069

Leland Woodall wrote:

Everyone,

To what temperature and duration must typical no-clean fluxes be exposed
before they are activated and be safely left on the board?

I've tried to contact Alpha to answer this, but haven't been able to
speak with a single technical rep all morning...

Thanks,

Leland




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