Fellow Technetters,

One major benefit of solder paste printing for BGA rework is simply to
maintain control of the flux volume that is used.  When rework operators are
working with no-clean Tak flux, it is harder to control- even with a
pneumatic dispensor.  I would say 95% of the time more flux is used in the
tac flux process as compared to the solder paste process.
The solder paste process is great for flux control on sensitive no-clean
assemblies such as for RF applications, but for speed and efficiency- and
water solable rework which will see a post rework cleaning step- the tak
flux process is surely a more cost effective solution.

Steve A
> -----Original Message-----
> From: Jeff Ferry [SMTP:[log in to unmask]]
> Sent: Thursday,January 31,2002 9:54 AM
> To:   [log in to unmask]
> Subject:      [TN] BGA Rework Using Paste vs. No Paste
>
> Fellow TechNetters,
>
> We nearly always apply solder paste to the circuit board when we replace
> BGA components during rework. Yet, after speaking with a handfull of BGA
> equipment companies at APEX, seems like they all recommend using flux only
> vs. paste, unless the circuit board is used in a high rel application.
>
> What do ya'all do/recommend for BAG rework? Can you point me to any
> studies/reports on the subject?
>
> Thanks,
>
> Jeff Ferry
> CEO
> Circuit Technology Center, Inc.
>
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