Mark,
In my opinion, no, it is not acceptable to leave these materials on a 
circuit board.  I have found them to be electrically conductve when 
unactivated and can be corrosive. 

How are you adding flux in the rework and touch up?  If you are squirting 
on large volumes, I think you have a problem.  If you are using a needle 
point dispenser that applies a drop at a time you are probably OK. Another 
possible alternative is to use fillable flux pens that have a fine 
paintbrush type tip. 

Doug Pauls



From:   "Woolley, Mark D. (Mark)" <[log in to unmask]>
To:     <[log in to unmask]>
Date:   04/23/2012 08:43 AM
Subject:        [TN] No-Clean Flux
Sent by:        TechNet <[log in to unmask]>



I have an issue with one of the assembly houses we use.  They are using
a No-clean flux that contains adipit and succinic acids (per the MSDS)
in an alcohol base.

Is it allowed to leave flux on the PWB that HAS NOT BEEN DEACTIVATED BY
HIGH TEMPERATURES OF SOLDERING?

I am not talking about the flux used in the solder paste or wave
soldered flus.  I am talking about the flux used at rework and touch-up
of the PWB.

 

I havce seen papers detailing corrosion on PWBs using "no-clean" fluxes
and I have seen it on some of our products.  This usually pccurs near
the periphery of the PWB where the wave solder flux is protected by the
pallet used to pass the PWB through the solder wave.

 

Any opinions and references will be appreciated.  I can give the
manufacturer and flux type to individuals, but don't want to put it in a
global email.

 

Thanks

mark

 

 

mark

Mark Woolley |PTRL Laboratory | Avaya | 1300 West 120th Ave |
Westminster, CO 80234  USA |

Voice (Lab): (303) 538-2166 | email: [log in to unmask] |

 


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