This is so. They have a GWP exceeding 10,000 times that of CO2. 2 kg of
the stuff emitted (and vapour is always trapped by components, no matter
what the makers say) causes more greenhouse gas effect (climate change)
than a car causes in all its lifetime. Note that PFCs are targetted in
the Kyoto Protocol and may be legislated locally (tax on an already high
price, government permission required or other restrictions, outright
ban). Happily, PFCs in the atmosphere are still only in the ppt range
but if they are allowed to increase, they could be restricted. Another
point to consider is they have an atmospheric residence time of >10,000
years, so about 350 g will remain in the atmosphere in the life of your
great-to-the-power of 25-grandchild, for every kg emitted today. Some
legacy!
In a way, it's a pity it's so bad environmentally, because it's damn
good for asymptotic reflow/soldering!
Brian
Brian
Kane, Joseph E (US SSA) wrote:
> Sorry, mis-spoke there.
>
> Perfluorocarbons have no ODP, problem is with global
> warming, because they trap heat much better than CO2
> or methane.
>
> -Joe
>
> -----Original Message-----
> From: Kane, Joseph E (US SSA)
> Sent: Monday, October 24, 2005 3:34 PM
> To: '(Leadfree Electronics Assembly Forum)'; 'Malewicz Wesley'
> Subject: RE: [LF] Vapor Phase Reflow Soldering vs. Convection Reflow
> Soldering
>
>
> We use convection also, but I've seen some operations recently with
> vapor phase.
>
> Vapor phase works great. Very efficient heat transfer, which is good
> when you have lots of thermal mass. Maximum temperature is limited to
> the boiling point of the fluid.
>
> On the downside, older models without good preheat can cause
> serious thermal shock. The perfluorinated chemistry is expensive and
> has high ozone depletion potential.
>
> Joe Kane
> BAE Systems
> Johnson City, NY
>
>
> -----Original Message-----
> From: Malewicz Wesley [mailto:[log in to unmask]]
> Sent: Monday, October 24, 2005 2:09 PM
> To: [log in to unmask]
> Subject: [LF] Vapor Phase Reflow Soldering vs. Convection Reflow
> Soldering
>
>
> Hello all,
>
> We are currently evaluating an EMS provider who is currently using a
> Vapor Phase Reflow system. I am most familiar with the Convection
> Reflow system and would like information from any one who can provide me
> with a pros and cons between these two types of soldering systems.
>
> Being a Medical products manufacturer, we are concerned that some BGA
> type components in the near future will not be available with solder
> balls containing Lead. Some new components already are only available
> as Lead Free. As a result on new designs, we now have a mix of these
> types of components. We are handling this by processing the PCB through
> the conventional Lead soldering process and adding the Lead Free BGA
> components through a work process.
>
> Any information you can provide on the pros and cons will be
> appreciated.
>
> Thank you,
>
> Wes
>
> Tel: +1 978-907-7776
> Fax: +1 978-907-6489
> E-mail: [log in to unmask] <mailto:[log in to unmask]
> <mailto:[log in to unmask]> >
>
>
>
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