I would also like to get a copy.
Debbie Kenney
Engineer
M-Flex / AMT
Direct (714) 688-5242
Fax (714) 996-3834
[log in to unmask]
> -----Original Message-----
> From: Gordon F. Davis Jr [SMTP:[log in to unmask]]
> Sent: Friday, June 21, 2002 4:30 AM
> To: [log in to unmask]
> Subject: Re: [TN] Cleaning of Military PWAs That Have Been Soldered
> withNo-CleanFlux
>
> May I get an e-copy of the paper you refered to as well. I also work for
> a
> military supplier, but we clean everything. I would like to get further
> info on no-clean.
>
> Gordon Davis
> Application Engineer
> Rockwell Collins
>
>
>
>
> David Douthit <[log in to unmask]>@ipc.org> on 06/20/2002 09:10:13 PM
>
> Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please
> respond
> to David Douthit <[log in to unmask]>
>
> Sent by: TechNet <[log in to unmask]>
>
>
> To: [log in to unmask]
> cc:
>
> Subject: Re: [TN] Cleaning of Military PWAs That Have Been Soldered
> withNo-CleanFlux
>
>
> You have landed in a very nasty area. You are correct to be concerned
> about
> contamination issues.
> Even if the residues from the flux do not create migration/leakage current
> problems they may
> collect other airborne contaminates that can cause problems.
>
> Process, shipping, and storage control are critical to the reliability of
> the circuitry.
>
> If you wish I have a paper I presented in May of 2001 titled
> "Avionics Systems, Reliability, and Harsh Environments"
> that I could e-mail you. The information in the paper will
> give you a good idea of what type of airborne contamination
> issues you may have to deal with.
>
> David A. Douthit
> Manager
> LoCan LLC
>
> Bogert wrote: 6/20/2002 Folks is anyone manufacturing military PWAs using
> no-clean flux and not cleaning the PWAs prior to shipment? If so, what is
> your reliability experience with this process? We are considering a
> military application (Class 2) where mixed technology (SMT and PTH) PWAs
> will be soldered using no-clean flux and then not conformal coated
> (assuming the uncoated PWAs can pass our temperature/humidity
> qualification
> testing). Although the no-clean flux we will use should be benign (we are
> having SIR testing performed to confirm this and Omegameter testing), I am
> concerned that contamination may be introduced by other shop processes
> such
> as mechanical assembly, testing, etc., even if one uses gloves or fingere
> cots during handling. One could argue that after shipment, since the PWAs
> are not conformal coated, you can introduce contamination in the field and
> therefore, why not not clean prior to shipment. We may be performing board
> testing (boundry scan, bed-of-nails, etc) on PWAs that have been soldered
> using no-clean flux. I understand that certain noclean flux can impede
> this testing, and also, may cause problems in event we need to conformal
> coat the PWAs. Any comments on this subject will be appreciated.
>
>
>
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