Peter & Gordon, If you have unactivated flux left after Wave Solder processing, are you not maybe using a bit too much flux? Also the fact that you're using a hot air rework station to activate the flux until it disappears means that you are subjecting your boards to unnecessary thermal excursions that will ultimately reduce the life of the board. Either that, or you're not using the correct temperatures to activate the flux in the first place. Just an unsolicited and gratuitous 2c's-worth. Peter Gordon McAlpine <[log in to unmask]> 20/09/2002 06:46 PM Sent by: TechNet <[log in to unmask]> Please respond to gordon.mcalpine To: [log in to unmask] cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group) Subject: Re: [TN] Noclean Wave soldering We currently use a no-clean process {no wash process} with our assemblies and have had the following issues to contend with. 1} Unactivated no-clean flux leaves a white residue on the board. Although this is non- corrosive it is unsightly to the customer. We have been using a hot-air rework station to remove this residue by activating the flux till it disapperars. 2} We did try at one point to try and clean the boards with a cleaner "prozone" but this is not recommended. The reaction between the flux and the prozone caused the areas applied to become hydoscopic and absorb moisture. The boards then started to "grow" a white residue almost powder like growth. 3} On hand soldering of parts after wave solder, we used to use the same flux that was in the solder bath, but although the board looks clean immediately after the sodlering process, if it is left for approx 24hours then this unactivated flux residue appears. We combat this by only using a rework gel flux for apply to the board before hand soldering. Hope this helps... On 19 Sep 2002 at 23:10, Peter Lee wrote: Date sent: Thu, 19 Sep 2002 23:10:26 -0700 Send reply to: "TechNet E-Mail Forum." <[log in to unmask]>, Peter Lee <[log in to unmask]> From: Peter Lee <[log in to unmask]> Subject: [TN] Noclean Wave soldering To: [log in to unmask] > Technet, > > Is anyone currently adopting a no clean flux/ no post wash with their > Wave soldering process? We had a few wave soldered products requiring > post hand soldering due to non-washable components (filters, > transformers etc.) > > In particular, I like to know what areas of concern you run into (eg. > Remaining Flux residues, conformal coating) and your feedback on the > overall cleanliness of the boards. > > > Rgds, > Peter > > --------------------------------------------------------------------------------- > Technet Mail List provided as a free service by IPC using LISTSERV 1.8e > 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) > 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 > --------------------------------------------------------------------------------- Best Regards Gordon McAlpine Test Engineering Manager Telspec Scotland Ltd Tel :- 01738 494500 DDI :- 01738 494506 Fax :- 01738-630012 E-Mail :- [log in to unmask] ================================================ DISCLAIMER This message is intended only for the use of the individual(s) or entity named above. It may contain information which is privileged or confidential. If you are not the intended recipient, please return it to the sender as soon as possible and be aware that any disclosure, copying, distribution or use of the contents is prohibited. The views expressed in this communication may not necessarily be the views held by the Company. --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) 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 --------------------------------------------------------------------------------- [This e-mail is confidential and may also be privileged. If you are not the intended recipient, please delete it and notify us immediately; you should not copy or use it for any purpose, nor disclose its contents to any other person. Thank you.] --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) 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 ---------------------------------------------------------------------------------