Sorry, Graham, but I insist. The residues of the flux itself contains a large excess of surfactants which lower the surface tension of the wash water to ~25-30 dyne-cm. Most saponifier solutions have an ST of 30-35 dyne-cm. The only effect that saponifiers would have is to replace the acid residues with equally corrosive alkaline ones. It's a waste of time and money adding saponifiers. Furthermore, if your wash cycle contains saponifier, you must have a second water-only wash cycle before the rinse starts, to wash off the saponifier residues. Not all machines permit this. What I said in my previous message still stands. A pre-rinse in a chelating neutraliser (which is NOT a saponifier), BEFORE washing is beneficial. This can be in a static hold tank. This is a time proven method. This is demonstrated in the streaming video at http://www.protonique.com/video/ (this is quite old and the components are BIG, but the principle is still valid). Brian Graham Naisbitt wrote: > Hello Mike > > I knew I shouldn't have.....but can't help myself...... > > I agree with you, but what I am referring to is the use of a closed-loop > pure water 'OA' type process where no chemistry is used only pure water. > > Surfactants to my knowledge are not used in isolation, saponifiers (soaps) > will be needed as well, and make sure the surfactant has excellent > rinseability (silicone base is not a good thing in this instance). Whatever, > it is wash chemistry and there will be an effect on the life of the filter > beds and the transfer of wash 'chemistry' getting into the rinse zone(s). > Clearly the use of saponifiers that generally have to include surfactants > for that very reason, require a somewhat more complex cleaning system. > >>From my perspective, the pure OA approach, as Brian alluded to in his reply, > isn't adequate to ensure thorough cleansing on high density low stand-off > devices. > > ...ah! That perennial question: How clean is clean? > > Graham Naisbitt > > >>Hello Graham: I have to disagree with your statement regarding the need for >>saponification to get under low standoff components. The need was to reduce >>surface tension which can be achieved with a surfactant. With a surfactant >>the surface tension of the wash water is lowered allowing it under low >>standoff components to flush out OA flux residues. It also does not leave >>behind the saponifier chemistry. >>Saponification is quite a different animal than a surfactant. The saponifier >>converts non water soluble residues to hydrophilic or water soluble ones. >>The saponifier typically has a surfactant as part of it's make up to allow >>better wetting or penetration but contains other components if not rinsed >>that can be detrimental to the electrical performance of the assembly. The >>obvious advantage of the saponifier is that it will remove other >>contaminates on the PCA besides the flux that are not water soluble. >> >>With that said we do use a saponifier but have very good process control on >>the types and angles of our spray nozzles in wash and rinse. Along with >>increasing temperature through the various rinse stages to facilitate the >>complete flushing and removal of the saponifier. >> >>Just a clarification as sometimes these two terms saponifier and surfactant >>are used interchangeably. >> >> >>Regards >> >>Michael Barmuta >> >>Staff Engineer >> >>Fluke Corp. >> >>Everett WA >> >>425-446-6076 >> >>-----Original Message----- >>From: Graham Naisbitt [mailto:[log in to unmask]] >>Sent: Tuesday, May 04, 2004 5:41 AM >>To: [log in to unmask] >>Subject: Re: [TN] OA / RMA >> >> >>I must be mad sending this to challenge The Oracle himself but.... >> >>The real beauty of the OA process is that it required only water - as >>distinct from Aqueous Process where Water Soluble, or some would say Water >>Washable fluxes were used that required some cleaning chemistry. >> >>Aqueous processes I always thought of as a misnomer and that it should be >>called Semi-Aqueous - ergo water only v water plus chemistry. >> >>However, the drawback with the Water Only approach is that it proved to be >>inadequate for some of the newer low stand-off devices such as micro-BGA, >>flip-chip and some of the smaller discreets <0604. Saponification had to >>added in order, not only to get under such devices but, more importantly, to >>get the darned stuff out from underneath including the "dissolved" >>contaminants. >> >>IMHO - Graham Naisbitt >> >> >>>I installed the first OA (misnomer, WS is better) full scale >>>wave-soldering production line in Switzerland (if not in Europe) as long >>>ago as 1965. The company in question is still using it,four soldering >>>machines later. I have since aided in many others, throughout the world. >>>Advantages of WS: >>>- better quality soldering with fewer rejects >>>- more tolerant of poorly solderable components >>>- widest operating window >>>- no expensive cleaning products >>>- minimal pollution from overall process >>>- lowest production costs >>>Disadvantages: >>>- requires good process control >>>- unforgiving of errors >>>- good quality cleaning equipment rarer than you think >>>- flux itself is fairly corrosive >>>Summary: >>>- requires a serious approach and qualification >>>- with this proviso, this is the way to go. >>> >>>Brian >>> >>>Dehoyos, Ramon wrote: >>> >>>> Hi Technetters: >>>> Has anybody done a comparison study of RMA/OA fluxes for >>>>wavesolder? Or any personal experiences in this regard will be >> >>appreciated. >> >>>> Thanks in Advance >>>> Ramon >>>> >>>>--------------------------------------------------- >>>>Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 >> >>>>for additional information, or contact Keach Sasamori at [log in to unmask] >> >>or >> >>>>847-509-9700 ext.5315 >>>>----------------------------------------------------- >>>> >>>> >>> >>>--------------------------------------------------- >>>Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 >> >>for >> >>>additional information, or contact Keach Sasamori at [log in to unmask] or >>>847-509-9700 ext.5315 >>>----------------------------------------------------- >>> >> >>--------------------------------------------------- >>Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 >>for additional information, or contact Keach Sasamori at [log in to unmask] or >>847-509-9700 ext.5315 >>----------------------------------------------------- >> >>--------------------------------------------------- >>Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for >>additional information, or contact Keach Sasamori at [log in to unmask] or >>847-509-9700 ext.5315 >>----------------------------------------------------- >> > > > --------------------------------------------------- > Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 > ----------------------------------------------------- > > --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------