Mike, I agree. I am in the process of evaluating a cleaning process for a client. I'll be required to suggest alternative cleaning technologies to what he is currently using. I had already mentally reserved what Shean is publicising as one possibility, but his unashamed post here is causing me to have second thoughts on the grounds that a company which ignores the netiquette of a forum may also ignore the ethics of commerce. Brian Michael Fenner wrote: > > Am I alone in feeling a little miffed by the response below? At the risk of being offensive to > Shean, however sincerely he might believe in what he says, I don't think this is the place for > outright product placements masquerading as answers. > > Mike > > ----- Original Message ----- > From: Shean Dalton <[log in to unmask]> > To: <[log in to unmask]> > Sent: Thursday, February 17, 2000 6:43 PM > Subject: Re: [TN] PWB CLEANING SOLVENTS > > > > > > > > > > > Hello Fellow Technetters, > > > > What an interesting forum!!! An alternative to in-line spray cleaners and > > spray under immersion wash systems is centrifugal cleaning. Spinning the > > PCB about it's center while immersed in a wash solution creates an angular > > acceleration that acts along the plane of the PCB. While the PCB > > alternates between clockwise and counter clockwise spinning motions, the > > angular acceleration converts the PCB's rotational energy into centrifugal > > cleaning energy. The centrifugal energy's magnitude AND direction are > > parallel to the plane of the PCB, ideal for cleaning underneath low > > profile, high density components. Centrifugal cleaning removes 100% of all > > entrapped flux residues beneath components when measured ionically (0.00 > > microg/in2) or visually at 30X. > > > > As was posted earlier, effective water removal can prevent downstream > > production problems; but, the evaluation of a cleaning equipment's ability > > to remove water is often over looked. Spin drying the PCB in the presence > > of heated, dry air causes 100% moisture removal and spot-free results in > > SECONDS. > > > > The effectiveness of Centrifugal cleaning reduces the number of required > > cleaning steps by eliminating repetitive cleaning cycles and additional > > drying steps. The reduction of cleaning steps provide for short cleaning > > cycle times (3-7 minutes), yielding a high through-put. > > > > Odors are eliminated by containing the cleaning process inside a sealed > > process chamber. If appropriate materials are used in the construction of > > the centrifugal cleaning system, solvent versatility is assured. And with > > an on board, closed loop waste water treatment system, No Drain is required > > and a single drum of solvent may last a year or more. > > > > To learn more about Centrifugal Cleaning Systems contact Speedline ACCEL at > > 972-424-3525 or visit our APEX booth #1547 and ask for information on the > > MicroCel. And, to paraphrase a previous posting, we'll be happy to help by > > providing free cleaning evaluations with parts submitted by you. > > > > Shean Dalton > > Speedline ACCEL > > > > > > > > > > (Embedded > > image moved Michael Fenner <[log in to unmask]> > > to file: 02/16/2000 11:44 AM > > pic12910.pcx) > > > > > > > > > > To: [log in to unmask] > > cc: (bcc: Shean Dalton/ElectrovertUS/Cookson) > > Subject: Re: [TN] PWB CLEANING SOLVENTS > > > > > > > > -------------------------------------------------------------------------------- > > IPA certainly improved 1.1.3 CFCs when added to them, but that's because > they were so useless, I > agree that IPA is not too brilliant on its own compared to alternative. > > However just as pertinent I think its also worth pointing out that it's > extremely flammable > and its bulk use renders the plant liable to all sorts of quite onerous > safety rules/regulations > and so on. > > Also whilst on this pragmatic note, whereas almost any semi-aqueous system > will very efficiently > remove flux, a major problem with them is not therefore flux removal but > water removal = drying. > This is often overlooked when carrying out trials, but actually constitutes > a significant > production problem which needs to be addressed with as great a priority as > material selection. > > Mike > > ----- Original Message ----- > From: Blomberg, Rainer (FL51) <[log in to unmask]> > To: <[log in to unmask]> > Sent: Wednesday, February 16, 2000 1:26 PM > Subject: Re: [TN] PWB CLEANING SOLVENTS > > Brian, > > I agree with you. Our bench cleaning procedure includes Axarel 2200 for > the > reasons you state. I'm looking for alternatives. Also, contrary to most > board assembly areas I've ever seen, we don't blow off/dry the dirty > solvent, we use a pretty good sized vacuum probe to immediately remove the > dirty solvent from the surface of the cleaned area. This is done > specifically to prevent the spread of contaminants as you mentioned. It > also > prevents the assembly area from smelling strongly of IPA by not turning the > liquid into an aerosol. A final, total board cleaning is performed in the > Axarel 32 batch cleaner to address the small remaining residue and items > that IPA can't. > > Thanks, > Rainer > > -----Original Message----- > From: Brian Ellis [mailto:[log in to unmask]] > Sent: Wednesday, February 16, 2000 3:37 AM > To: TechNet E-Mail Forum.; Blomberg, Rainer (FL51) > Subject: Re: [TN] PWB CLEANING SOLVENTS > > Rainer > > There is hardly a worse cleaning solvent for RMA fluxes than IPA. At the > best, it will > spread the soluble rosin over a larger area, until it is thin enough to be > invisible. > This increases the surface area so that any dangerous contaminants, such as > those > ionics that are soluble in IPA are more readily accessible to cause harm. > Furthermore, > IPA is VERY poor at dissolving the metal-organic salts formed by reaction > between the > flux and the oxides and will do so ONLY if it is virtually 100% pure: > saturation occurs > at ppm levels. > > It became popular because of the erroneous belief that what is used for > formulating a > liquid flux must be good for cleaning off the residues. This hypothesis > ignores the > facts a) that certain components, including the rosin, are much modified by > heating to > over 200°C and b) there are chemical reactions occurring that modify the > residues. > > Beware! > > Brian > > "Blomberg, Rainer (FL51)" wrote: > > > Hans, Faz, > > > > I am currently in the middle of a cleaning improvement investigation and > > could share some info. Hans, I have found a spray-under-immersion batch > > cleaning machine which is getting strong consideration. It is made by > > Austin America (Mega II) and is compatible with aqueous and semi-aqueous > > cleaning solvents. It has a lot of nice features that might suit your > > needs. > > > > Faz, for your information, we use RMA flux on space quality assemblies > and > > are using IPA and Axarel 2200 for hand cleaning at the bench and using > > heated Axarel 32 in our ECD spray-in-air (nitrogen) batch cleaner > followed > > by hot DI water rinsing, IPA spray off and oven drying. It's a long > process > > that we are looking to shorten. Operators don't like the solvent smell > and > > use IPA/brush/vacuum probe almost exclusively with great success. IPA is > > inexpensive, relatively safe and effective for small touch-up type work. > > Complete board cleaning does indeed have many options and the type of > flux > > is the biggest driver of which is "best". We are currently exploring > > long-chain alcohol like Kyzen Ionox I3330 to do the job of several > solvents. > > We have found it to clean both RMA and NC fluxes from wave and hand > solder > > operations equally well in immersion type equipment. I understand it is > > also available in a bench cleaning formulation. It may well turn out to > be > > our "best" choice, but you have to judge your application independently. > In > > another application (military boards), an in-line cleaner using Bioact > EC-7 > > works well, but didn't clean well enough (too much white residue) for the > > space application boards. You can't predict cleaning effectiveness > > beforehand, it's something you have to tailor to your situation. I know > > that's not much help, but equipment and chemistry suppliers can help by > > providing free cleaning evaluations with parts submitted by you. > > > > Good luck. > > > > R. G. Blomberg > > Honeywell - Space Systems > > Staff Production Engineer > > (727) 539-5534 voice > > 727-539-4469 Fax > > [log in to unmask] > > > > -----Original Message----- > > From: Hinners Hans Civ WRALC/LYPME [mailto:[log in to unmask]] > > Sent: Tuesday, February 15, 2000 9:03 AM > > To: [log in to unmask] > > Subject: Re: [TN] PWB CLEANING SOLVENTS > > > > Hi Faz, > > > > You're in luck. I'm using Kester 186 and 186-18 RMA fluxes with their > 5738 > > Dross Inhibiting Fluid. We do a mix of thick (150 mil) multilayer and > not > > so think double sided boards and assemblies. We wave solder using an old > > (translation: museum quality) Hollis machine. > > > > First, we do a cascade wash with hand brushing in Trans LC (Trans 1, > > 2-Dichloroethlyne) which replaced Trichloroethylene (the environmentally > bad > > stuff not the less bad stuff). I'm looking for a substitute. It cleans > > great but has health & safety issues I'd like to eliminate. If we were a > > bigger outfit I'd prefer an immersion spray washer if one exists for PCBs > > (hint hint). Depending on the board a cascade rinse in isopropyl alcohol > > can do the trick or skipping it all together. I've tried some other > stuff > > but haven't found it yet, some are so aggressive they'll strip the > > silkscreen printing off or change the appearance of the board. I just > hate > > when that happens. > > > > Next, we run the boards through our Tooltronics Ultra Clean II Aqueous > > Cleaner with Kyzen's Aquanox XJN chemistry at 25% strength (minimum). > The > > boards get washed for 2 to 3 minutes (depends on the conveyor speed) at > ~35 > > psi. Lighter stuff goes in baskets with lids. A two stage DI Water > rinse > > for 3 - 4 minutes. Aquanox XJN is very good at rinsing clean and it > takes > a > > while to load up. We used to run Armakleen (before my time) but it never > > stayed active long enough to pay for itself. Plus it would scale the > pipes > > up something awful. What supply we have left is used in one of our dish > > washers. > > > > Depending on the assembly, we also dry with compressed air (Nitrogrn line > > coming soon!) and store in Nitrogen cabinets. > > > > We're a small shop so I'm not sure how portable this info will be. > > > > Hans > > > > ~~~~~~~~ > > Hans M. Hinners > > Materials (& Process!) Engineer > > Warner Robins - Air Logistics Center/Avionics Production Division > > Manufacturing Branch (LYPME) > > 380 Second Street, Suite 104 (Building 640) > > Robins AFB, GA 31098-1638 > > 912-926-1970 (Voice) 468 - 1970 (DSN) 912-926-7164 (Fax) > > mailto:[log in to unmask] > > . > > > > > -----Original Message----- > > > From: Dan Fazioli [SMTP:[log in to unmask]] > > > Sent: Thursday, February 10, 2000 02:11 > > > To: [log in to unmask] > > > Subject: [TN] PWB CLEANING SOLVENTS > > > > > > Greetings, TechNetters! > > > > > > I have a question for the "guru's" of PWB cleaning, and obviously it > > > relates to > > > the new legislation (Montreal Protocol) which now bans the use of Ozone > > > depleting substances containing CFC based materials. So, with that in > > > mind...."What are the best "cleaning solutions" (chemicals) to use > which > > > are > > > most effective for removing the flux residuals from PWB's that also has > > > compatibility with a wide variety of different chemicals and materials > > > such as > > > adhesives, connectors, sleeving, wire, inks, epoxies and etc.?" In > > > essence, > > > we all know that establishing a suitable substitute is no small task, > and > > > involves many trade-offs as well. However, I would appreciate anyone > > > sharing > > > their experience with regard to this endeavor. > > > > > > Best regards, > > > > > ############################################################## > TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c > ############################################################## > To subscribe/unsubscribe, send a message to [log in to unmask] with following > text in > the body: > To subscribe: SUBSCRIBE TECHNET <your full name> > To unsubscribe: SIGNOFF TECHNET > ############################################################## > Please visit IPC web site (http://www.ipc.org/html/forum.htm) for > additional > information. > If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or > 847-509-9700 ext.5365 > ############################################################## > > ############################################################## > TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c > ############################################################## > To subscribe/unsubscribe, send a message to [log in to unmask] with following text in > the body: > To subscribe: SUBSCRIBE TECHNET <your full name> > To unsubscribe: SIGNOFF TECHNET > ############################################################## > Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional > information. > If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or > 847-509-9700 ext.5365 > ############################################################## -- Brian Ellis Protonique SA PO Box 78 CH-1032 Romanel-sur-Lausanne, Switzerland Voice: +41 21-648 23 34 Fax: +41 21-648 24 11 E-mail: [log in to unmask] URL: Technical and consultancy divisions: http://www.protonique.com Web services division: http://www.protonique.com/webserv ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. 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