Chris Might you be able to share with us what tests you employed to validate / qualify the process? Graham Naisbitt On 7/9/05 18:46, "Schaefer, Chris" <[log in to unmask]> wrote: > I agree with Edwin if you are using an inline process or possibly a batch type > cleaner. We are converting to a rosin base flux with a solids of 15% and plan > to use the Kyzen A4520 product (surfactant base) soap for the flow solder > process to enable us to more effectively solder Pb Free components. We have > performed extensive and very expensive tests to validate/ qualify this > chemistry and found the following: > > - Lower temperatures in the wash bath (thus reducing evaporative > losses and other advantages) > - Longer bath life than the previous version of soap by 1.5X depending > on pcb cleaning volumes and added soils from wave/ smt > - Greatly improved cleaning underneath fine pitch components > - Increased cleaning speeds (single pass vs. dual in some cases) > - "Capable" of cleaning lead free soldering processes > - Shinier joints if aesthetics are important to you or your customers > - Reduced Surface Organics > - Lower ionics > - any other positive items > > ***Note: This is not a commercial for their chemistries, just personnel > experience with them.*** > > We are using an AS200 inline water wash with a level 4 chemical isolation to > aide in the reduction of chemical loss due to dragout/ bath to bath migration > and Hurricanes to improve cleaning as well. Once we have completely converted > over to Pb free soldering in all aspects, we will change the A4520 to the > A4630, which is to be their cleaning chemistry for Pb Free soldering > processes. We are to begin trials of this material by the end of the year. > > *** > To answer another question concerning Tin/ Lead soldering profiles vs. ENIG > profiles - we have processed both of these plating types in both the smt and > flow solder processes without deviating from the original profiles depending > on the flux type used. The results between the 2 plating types was little > difference (if any) using a higher solids content flux 15% RMA, but when using > a lower solids content NC flux (2%) we have had to reduce heat (if possible) > and/ or increase conveyor speed to allow the flux to last longer. This of > course would allow reduced surface tension of the flow solder wave enough once > the PCB contacted the surface to allow for best possible soldering. > > *** > > Chris Schaefer > Suntron Corporation > Process Engineer > 540 N. Rogers Road > Olathe, Kansas 66062 > 913.393.5878 > [log in to unmask] > > NOTICE: > > This message is intended for the use of the individual entity to which it is > addressed and may contain information that is privileged, confidential and > exempt from disclosure under applicable law. If the reader of this message is > not the intended recipient, or the employee or agent responsible for > delivering the message to the intended recipient, you are hereby notified that > any dissemination, distribution or copying of this communication is strictly > prohibited. If you have received this communication in error, please notify us > immediately by calling 913.393.5878 or returning the original message to us. > > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]]On Behalf Of Edwin Louis > Sent: Wednesday, September 07, 2005 6:57 AM > To: [log in to unmask] > Subject: Re: [TN] Cleaning rosin flux residues > > > KYZEN makes cleaners that can remove the rosin residues. Ides a cleaning > chemical, you need agitation. Are these PWAs going through an in-line > cleaner? Call Mike Bixenman at 615-584-9089. > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Paul Klasek > Sent: Wednesday, September 07, 2005 6:40 AM > To: [log in to unmask] > Subject: Re: [TN] Cleaning rosin flux residues > > On the root cause Juan, > the 'white stuff' (be flux) should not have creep that far normally > (granted nothing is normal) : traced this occurrence in same incidence > (test) to flux overspray (& bake); perhaps check if wave pass applies. > > -----Original Message----- > From: Brian Ellis [mailto:[log in to unmask]] > Sent: Wednesday, September 07, 2005 6:24 PM > To: [log in to unmask] > Subject: Re: [TN] Cleaning rosin flux residues > > > IPA is one of the worst cleaning solvents: its only merit is that it is > polar. If, as you surmise, the residues come from your flux, then they > are probably a nasty mixture of thermally polymerised and probably > hydrolysed rosin, along with some residual activators. I am making a > guess that your flux is "halogen-free", because this kind of flux can be > the very devil, whether rosin based or not, because the activator > content is essentially some form of carboxylic acid in much higher > proportions than you get in organic chloride/bromide type fluxes and > some of them can polymerise at the drop of a hat. > > Isn't the use of HCFC-141b as a solvent forbidden in the EU, anyway? > > Now you have a double-whammy of a problem: not just nasty residues, but > deep in the contacts of a female connector. In this case, my first > reaction is that an ounce of prevention is worth a kg of cure: change > your connector to one whose design prevents any chance of the flux > wicking into the contacts (turned contacts, instead of pressed). If this > is not possible, then pre-tin them using minimal quantitites of flux, > such as a good W/S flux, and thoroughly clean, then use little or no > flux for the assembly. Another tip is to fill the contacts with a tight > PTFE plug during the tinning/soldering process, to physically prevent > flux from entering where it didn't ought to. > > Now, how to clean inside, where you already have contamination. Bearing > in mind the blind nature of the parts, you need both chemical and > mechanical help. You need an expensive solvent and HCFC-225ca/cb with an > azeotropic blend of methanol will probably be your best bet (much less > aggressive than HCFC-141b). For the mechanical side, think in terms of > an interdental toothbrush from your local pharmacy modified to fit in > one of those small, high-speed, hand-held drills. Soak the parts in the > solvent for a minute or two and insert the brush at, say, 10,000 rpm in > each contact, while flooding it with the solvent from a wash bottle. > Rinse in clean solvent. > > There are two problems with this: the solvent is toxic and it is > environmentally harmful, so you need very good ventilation drawing air > away from the operator and you need a carbon filter in the ventilation duct. > > If you can't get HCFC-225 (made only by Asahi Glass in Japan under the > trade name AsahiKleen), then try HFC-4310 (DuPont) or HFE (3M), also > blended azeotropically with methanol. They are less aggressive than the > HCFC-225 blend, but equally expensive (or more so). Many blends of HFCs > and HFE contain trans-dichloroethylene and should be avoided if you have > compatibility problems with HCFC-141b as this solvent (t-DCE) is even > more aggressive. > > Brian > > Juan T. Marugán wrote: >> Hello teachers, >> >> we have the following problem in some class 3 units: we have detected a >> white stuff inside the contacts of female connectors. It could be the main >> cause of the failures found during testing. Our thought is this substance >> could be due to a reaction between the rosin flux used when soldered the >> connectors whit the cleaning solvent (IPA) >> >> Two questions: >> >> 1) Could you recommend a solvent to remove these residues. We have tried >> with 141-b, but it could damage some parts of the unit. >> >> 2) We would like to send a contaminated connector to a lab for analisys. >> Could you recommend a technique to determine these substances? >> >> Thank you for your help. >> >> Juan T. Marugán >> Indra Sistemas SA >> Espańa >> >> --------------------------------------------------- >> 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 > 847-615-7100 ext.2815 >> ----------------------------------------------------- >> --------------------------------------------------- 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 847-615-7100 ext.2815 -----------------------------------------------------