CFCs have never been used as the primary liquid in VPS. The liquid is a
perfluorocarbon derivative which has two major disadvantages:
- it is horrendously expensive
- it is the world's worst greenhouse gas (an honour shared with sulfur
hexafluoride) with a climate change effect over 10,000 times worse than
CO2 and an atmospheric residency time in the many thousands of years. If
you emit 1 kg of the vapours today, your
great-to-the-power-of-40-grandchildren will still be suffering from your
carelessness. The real problem is that some of the vapour will be
trapped under components or in windings of inductors after soldering, no
matter how good the extraction and capture of the vapours are. That
means you would be causing great stress to the equilibrium of the
planet. 2 kg lost/year (typical in a good machine used well) is
equivalent to the CO2 emitted by a medium car in its whole lifetime.
My recommendations: although VPS is technically a good solution, it
should be used only when absolutely no alternative exists, as an
absolute last choice. If used, every effort must be made to capture as
much of the emissions as possible.
Remember also PFCs are targeted in the Kyoto Protocol as a controlled
substance; if your country has ratified it, you may be subject to controls.
CFCs were used only as a secondary blanket to limit emissions of the CFCs.
Brian
Denis Ryskamp wrote:
> Mike and all
>
> I am sorry, the wave solder unit had Nitrogen! I hate Mondays!
> In regards to the Vapor Phase unit, statement was made that the liquid used
> was a Teflon base not CFC like in the past.
> I am curious if others have found the results of vapor phase on a lead free
> board of quality equal to the current Tin Lead.
>
> Denis
>
> -----Original Message-----
> From: Leadfree [mailto:[log in to unmask]]On Behalf Of Mike Fenner
> Sent: Monday, April 25, 2005 11:48 AM
> To: [log in to unmask]
> Subject: [spam] Re: [LF] lead free vapor phase reflow
>
>
> Yes VPR is making a putative comeback in Europe just now on the back of
> Pb-free. The benefit of Vapour phase (or condensation reflow to give it an
> earlier name) is that it is an equilibrium process and once work has reached
> the temperature of the vapour no further heating takes place, thus the
> maximum temperature is intrinsic to the process.
> In a saturated vapour system the air can be virtually completely displaced
> by the vapour and this would give an anaerobic environment just like a
> nitrogen atmosphere as stated. Not all machines use a saturated environment.
>
> So far so good, how well the machine works in practice is down as always to
> engineering. For example The actual residual oxygen content will depend on
> the stability of the vapour blanket under production loading rather than at
> rest.
> I suggest you need to look at a couple of these to make user that the
> benefits on paper are realised in metal, and suit your work rate
> requirements at an affordable cost. There is no question that some of these
> machines work well in low volume prototyping as they are hard to get badly
> wrong, VPR is particularly suited to large boards with heavy thermal
> loadings. Others are a little optimistic in their aspirations.
>
>
> Regards
>
> Mike Fenner
> Indium Corporation, UK
>
> T: + 44 1908 580 400
> M: + 44 7810 526 317
> F: + 44 1908 580 411
> E: [log in to unmask]
> W: www.indium.com
> Pb-free: www.Pb-Free.com
>
>
>
>
>
>
> -----Original Message-----
> From: Leadfree [mailto:[log in to unmask]] On Behalf Of Richard Kraszewski
> Sent: Monday, April 25, 2005 4:22 PM
> To: [log in to unmask]
> Subject: Re: [LF] lead free vapor phase reflow
>
>
> There is a European company which tends to still be very actively involved
> in VP soldering for lead-free. I would guess they can at least point you in
> the right direction. Contact information is as follows:
>
> EPM-IBL
>
> Their North American Distributors are @
>
> WEB Site http://www.aictechnologies.com Email: [log in to unmask]
>
> Hope this helps.
>
>
>
> Rich K KEDS
>
> Phone: 260.925.8719
>
>
>
>
>
> -----Original Message-----
> From: Leadfree [mailto:[log in to unmask]] On Behalf Of Denis Ryskamp
> Sent: Monday, April 25, 2005 10:00 AM
> To: [log in to unmask]
> Subject: Re: [LF] lead free vapor phase reflow
>
>
> Hello all.
>
> Just returned from evaluating an EMS provider. The company is using a vapor
> phase reflow system (using a Teflon based liquid). The claim is that the
> temperature used is 230°C max and using a nitrogen atmosphere. Has any one
> had experience with this type of reflow? If so, what were the results?
>
> Thanks,
> Denis
>
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