Brian:
Two more, how long do you immerse them in the neutralizer? What are the neutralizers that you recommend?
Regards,
Ramon
> -----Original Message-----
> From: Brian Ellis [SMTP:[log in to unmask]]
> Sent: Wednesday, May 05, 2004 9:24 AM
> To: Dehoyos, Ramon
> Subject: Re: [TN] (2) [TN] OA / RMA
>
> I'm opposed to the use of saponifiers with water-soluble fluxes. They
> are as difficult to remove as the flux itself and just as dangerous. As
> I intimated elsewhere, a chelating neutraliser in a hold bath, before
> washing, may be advantageous. A saponifier is an aggressive chemical
> designed to solubilise insoluble carboxylic acids, such as rosin, by
> turning them into a soap. As, by definition, water-soluble fluxes don't
> normally contain insoluble carboxylic acids, what is the point of using
> yet one more aggressive chemical to do something it cannot do, with the
> additional risk of its precipitating metal salts because of its high pH????
>
> Brian
>
> Dehoyos, Ramon wrote:
> > Brian:
> > Based on your experience, is there a need for a saponifier in the cleaning of OA fluxes to ascertain residue removal from difficult parts to clean such as low BGAs and flip chips?
> > Regards,
> > Ramon
> >
> >
> >>-----Original Message-----
> >>From: Brian Ellis [SMTP:[log in to unmask]]
> >>Sent: Wednesday, May 05, 2004 7:33 AM
> >>To:
> >>Subject: Re: [TN] (2) [TN] OA / RMA
> >>
> >>YES!!!! Bingo!
> >>
> >>Brian
> >>
> >>Graham Naisbitt wrote:
> >>
> >>
> >>>Brian
> >>>
> >>>Thank-you for that information, it is most helpful albeit a little late for
> >>>the customer in question - 1998!
> >>>
> >>>...but let me get this straight - the residues of an OA flux (some or all?)
> >>>will serve to lower the ST sufficiently to assure good cleaning performance,
> >>>yes?
> >>>
> >>>Graham Naisbitt
> >>>
> >>>
> >>>
> >>>>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
> >>>>>>>>
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