Unfortunately, too true, Mike.
Although you sent me this as a PM, I've taken the liberty of reverting
it to Technet because what you say is of grave consequence to all of us.
As a long-standing member of the "environmental lobby" with decades of
experience in the field at governmental and intergovernmental levels, I
remain first and foremost a scientist/engineer. As such, I'm not a "box
ticker" but a reasonable and reasoning human. It is for this reason that
I have always distanced myself from the ecopolitical NGOs like
Greenpeace, FoE etc. For example, I was vociferously opposed (and still
am) to the lead-free fiasco, because I could find no reason for lead to
be hazardous to anyone or the environment on properly recycled
electronics assemblies at any stage of their life cycle. I tried to
intervene in the early consultancy stages before RoHS, requesting that
scientific risk assessment be carried out, to be told that such was
impossible for lack of funding. So costly legislation was promulgated on
zero scientific grounds. Someone ticked the 'lead is bad' box!
Brian
On 29/02/2012 11:44, Mike Fenner wrote:
> Morning Brian
> Interesting to read your thoughts as always. I fear though you may have
> confused the matter with logic. I would put a beer on it, but not a case,
> that someone has just ticked the no halide box, just to be sure.
> We now live in a world of world of bad science which is dominated by
> oversimplifications arising from the environmental lobby who seem almost
> able to pursue a no risk at any cost policy within the EU. (I am so glad to
> be out of trying to second guess regulations which change quicker than
> product development cycles etc).
> This means halides are now classified bad. At the same time modern
> management and our litigatious world means risk aversion and due process
> rule rather than outcome, so people just tick boxes. So as I say someone has
> just ticked the no halide box, and if that's the case for sure won't un-tick
> it, and they won't explain it either.
>
>
> Regards
>
> Mike
>
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Brian Ellis
> Sent: Wednesday, February 29, 2012 7:49 AM
> To: [log in to unmask]
> Subject: Re: [TN] halides in water soluble fluxes
>
> You have roused my curiosity, Phil. What are the parts that can
> withstand halide-free WS fluxes but not halide-containing ones, and why?
> I could understand it for some chemical sensors but optical??? Have you
> discussed this with your parts manufacturer? Does he give a reason for
> eschewing halides or is it aqueous processes that he does not like? What
> is his view on halide-containing rosin fluxes?
>
> Please let me warn you that you would need to re-qualify your process
> because you may find that the halide-free fluxes may be a lot more
> difficult to clean, especially with a DI-water only wash. You may find
> that there may be more corrosive residues on the washed boards.
>
> For me, assuming that my thoughts are justified, using your current
> process with one small modification, perhaps not requiring
> re-qualification, will fill the bill. That is to have a static bath
> containing a chelating neutraliser (not a saponifier) between the
> soldering and cleaning operations. A couple of minutes or so will
> solubilise any heavy metal halides or organic halides and will "kill"
> the excess acidity of any WS flux. I used to recommend Lonco 2051-B-3
> but I think this is no longer available. I think Alpha have one called
> Rinse-Aid and I suppose Kester, Multicore etc. may have equivalents.
>
> Have you thought that many components are supplied with halides galore?
> Component manufacturers often use halide fluxes for tinning their
> products, often with little or even no cleaning. Much tinned copper wire
> uses a zinc chloride/hydrochloric acid flux and the only cleaning is
> running it through a damp sponge followed by a sponge with a waxy substance!
>
> If your components are really sensitive to halide ions, I would say that
> ion chromatography will be an essential part of your qualification
> process, no matter which flux you use.
>
> Finally, have you thought about using your existing process but adding
> the sensitive components by hand, soldering with an evaporative
> halide-free no-clean flux, after cleaning? this may a simple cheap way
> round your problem, especially if the quantities are small.
>
> Brian
>
> PS Inge: Thanks for the plug. The IPC were kind enough to allow me to
> mention the availability of the book on this forum a few months ago but
> I don't want to abuse their hospitality, other than to say there is now
> a download version as well as the hard copy. I'm now the publisher as
> well as the author!
>
>
>
> On 28/02/2012 21:12, Phil Nutting wrote:
>> We have some parts that are sensitive to halides in flux, specifically
> some thru-hole opto devices. We are currently using a water soluble flux
> that contains halides. In doing some very quick research it looks like the
> WS fluxes have halides and the NC fluxes do not.
>>
>> Is there a halide free WS flux for lead-free wave soldering (foam
> application)?
>>
>> We need the WS fluxes because we currently use a DI water only batch wash
> system. Washing the boards is mandatory for our applications.
>>
>> Thanks in advance,
>>
>> Phil Nutting
>> Design for Manufacturing Engineer
>> Kaiser Systems, Inc.
>> 126 Sohier Road
>> Beverly, MA 01915
>> Phone: 978-922-9300 x1310
>> Fax: 978-922-8374
>> e-mail: [log in to unmask]<mailto:[log in to unmask]>
>> www.kaisersystems.com<http://www.kaisersystems.com>
>> www.linkedin.com/in/philnutting<http://www.linkedin.com/in/philnutting>
>>
>>
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