Well said, Graham.
Ken Robertson.
> Having been properly reprimanded for a posting many moons ago that was far
> less an advertisement than this, kindly refrain from such blatant commerce
> on this site.
>
> I trust, and am sure that Jack will follow-up to explain why in his own
> inimitable style.
>
> My only technical observation is to cast doubt on the proportion of
> attrition at the surface that can properly disperse said contaminants.
> Further, until you run SIR or indeed IC tests on properly prepared samples,
> I doubt the validity of your statements.
>
> Regards,
> Graham Naisbitt
>
> [log in to unmask]
>
> WEB: http://www.concoat.co.uk
>
> CONCOAT Ltd
> Alasan House, Albany Park
> CAMBERLEY GU15 2PL UK
>
> Tel: +44 (0) 1276 691100 Fax: +44 (0) 1276 691227
> ----- 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,
> > >
>
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