Doug
IMHO, you can only benefit, both technically and economically, by doing what you
propose, provided you go about it correctly by qualifying your new process. You will
get better soldering quality and better cleanliness if you choose your chemistry well.
Brian
Hooper Doug wrote:
> I am currently using a 4% saponifier solution in a manual parts washer
> unit. However, I think I could utilize water soluable flux and eliminate
> the saponifier. I have the ability to produce large quantities of hot DI
> water to wash my PWB assemblies. As long as I can thouroughly clean my
> assemblies and prove it (since I would be using water soluable flux as
> opposed to RMA) is there any reason I would not want to eliminate the
> saponifier?
>
> Douglas A. Hooper, Sr.
> Technical Training Instructor
> Luminescent Systems Inc.
>
> -----Original Message-----
> From: Douglas Pauls [SMTP:[log in to unmask]]
> Sent: Friday, February 11, 2000 7:37 AM
> To: Hooper; TechNet
> Subject: RE: [TN] PWB CLEANING SOLVENTS
>
> In a message dated 02/10/2000 2:24:29 PM US Eastern Standard Time,
> [log in to unmask] writes:
>
> >
> > I have a question for the "guru's" of PWB cleaning, and obviously it
> relates
> > to the new legislation (Montreal Protocol)
>
> ??New???
>
> > 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.?"
>
> That depends. Define compatibility.
>
> > 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.
>
> Wow, I haven't had an ODS alternative question for three years or so.
> Figured it was a dead issue. When the Montreal Protocol was put into
> effect
> in the late 1980s, and Congress nailed the coffin shut with the Clean Air
> Act
> of 95 (?), most manufacturers saw the writing on the wall and started
> working
> towards alternatives. In my experience, most military contractors went
> the
> route of staying with high solids rosin fluxes, but changed to
> alternative
> cleaning. This was driven primarily by the MIL-STD-2000A contracts,
> which
> only got painful if you went to a "non-rosin" flux, like a water soluble
> or
> no clean. Some tried to go the route of HCFCs, using products such as
> Genesolv 2004, but it was not long before the EPA put HCFCs in the same
> bad
> class as CFCs. Most contractors then transitioned to semi-aqueous
> cleaning,
> such as Axarel or Bioact.
>
> The IPC had a program in place to evaluate alternative cleaning materials
> and
> processes. The benchmarking of Freon TMS was written up in IPC-TR-580.
> A
> brilliantly written document (guess who). In Phase 2 of the program, the
> benchmark test was repeated for many different cleaning materials and
> technologies. Somewhere in my archives I have the final listing of all
> of
> the products which passed that testing protocol. EMPF, while still in
> Indianapolis, did most of the testing. You might get copies of those
> reports
> from either EMPF (now in Philly) or from Petroferm in Fernandina Beach,
> Florida, who now sells most of the materials on that list. The Test
> Monitoring and Validation Team (TMVT), which I chaired, was disbanded
> some 4
> or 5 years ago due to lack of further testing to monitor. The IPC also
> had
> several Phase 3 efforts, looking at water soluble flux, low solids flux
> in
> air, and low solids flux in nitrogen, and how they compared to the Phase
> 1
> Benchmark.
>
> While the move from ODS materials was painful for most, I think it
> produced
> better hardware in the end. Freon was not really a very good cleaner,
> but it
> had a good blend of properties. I see much better cleanliness levels now
> from saponified cleaning than I ever saw from Freon or Trike. The change
> forced most manufacturers to REALLY look at their process and understand
> the
> materials and materials compatibility issues involved.
>
> Bottom line: if you asked me today what one method would I invest in as
> an
> ODS cleaning alternative, I would choose aqueous cleaning with deionized
> water (140F min) with the addition of a good saponifier. Contact me off
> line
> if you are interested in my saponifier of choice.
>
> Doug Pauls
> Technical Director
> CSL
>
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--
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:
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