Doug, It appears that they flooded the area for a component with the flux prior to soldering the component. I have always recommended the use of No-clean flux pens that are used only on the pads (or the row of pads for fine pitch devices) the flux pen limits the amount of flux that is applied to the board, as well as limiting the area where the flux remains. In this case the assembly house did not do this. 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] | From: [log in to unmask] [mailto:[log in to unmask]] Sent: Monday, April 23, 2012 7:57 AM To: TechNet E-Mail Forum; Woolley, Mark D. (Mark) Subject: Re: [TN] No-Clean Flux 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] | ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________