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. --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------