Dave,
How do we know the impact of these VP fluids in reality? Can you prove or
is everything based on lab and theory?

Inge




On 8 December 2012 01:00, David D. Hillman <[log in to unmask]>wrote:

> Hi Brian!  It is rare but I disagree with you on one point in your
> details. As a society we seem to jump to the "let's ban" option far too
> often. I would offer a different approach - let's make the system more
> efficient and less wasteful. We have enough smart engineers that we should
> be able to design systems where the fluid loss is very very low or
> potentially zero. I understand that would make systems more expensive but
> then we would truly find out where Vapor Phase soldering is really
> necessary. Rockwell Collins utilizes Vapor Phase soldering as it is the
> most efficient and effective way to solder some of our thermally demanding
> designs. Condensation soldering has its place with our other soldering
> methodologies and should be used in a responsible manner. We have all
> witnessed the impact of the environmental legislation where many of the
> substitutions are more harmful to the environment than the material that
> was banned. Our goal should be a balance - ban materials where acceptable
> substitutes are available, be more controlled and efficient with materials
> that have no substitutes and submit to recovery/recycling practices to the
> largest extent possible.  As a  material engineer, I don't believe banning
> the use of materials is always the best approach. I know you are a
> champion the balanced approach so I believe the same approach could be
> used for Vapor Phase fluids.
>
> Dave Hillman
> Rockwell Collins
> [log in to unmask]
>
>
>
> From:   Brian Ellis <[log in to unmask]>
> To:     <[log in to unmask]>
> Date:   12/07/2012 12:26 PM
> Subject:        Re: [TN] Termination finishes, Cu thickness under Ag,
> Au-Pt-Pd
> Sent by:        TechNet <[log in to unmask]>
>
>
>
> I agree with you, Bev. If you lose only 1 kg of the stuff this year, on
> a linear scale (in reality exponential, but the difference is small),
> there will still be about 990 g of it floating round the earth, warming
> it, 100 years from now, 980 g in 2 centuries, 900 g in 3012 and 500 g in
> somewhere round 10012. In each year, in that time, your 1 kg will have
> the same effect as if you had burnt fossil fuels producing about 10
> tonnes (yes, 10,000 kg) of CO2.
>
> Is that a legacy you want to leave your children, grand-children,
> great-grand-children up to your great^25-grand-children?
>
> The problem is that the fluid has to be stable for more than 5 minutes
> while boiling at the temperature of soldering and the vapour has to have
> high density. These factors preclude any organic substance with a C-H
> covalent bond or any element with a single electron missing (Group VIIB)
> in its outer ring other than fluorine, which has an extremely tight
> bond. Even chlorine, the next one down, has a weak bond which would be
> rapidly destroyed at soldering temperatures, so would be useless for the
> job. This implies that the substance must be perfluorinated, whether a
> complex alkane or cyclic compound. The problem starts in that the
> covalent bond is so darned strong that there is no widely available
> natural mechanism, such as hydrolysis, to break the substance down; it
> requires pyrolysis at >1000°C to do so. The occasional molecule may be
> split by a collision with a high-energy radiated particle and this is
> why most perfluorinated substances have atmospheric residence times of
> the order of thousands or tens of thousands of years - without those odd
> collisions, the lifetime would be infinite.
>
> In practice, as the perfluorinated substances are so inert, it is
> unlikely they would bond with anything on a printed circuit assembly but
> the odd molecules could be imprisoned in the molten flux residues or
> simply trapped under components. This is why you lose your kg or so of
> fluid each year, no matter how good your machine is at recovering as
> much vapour as possible, either by long freeboard dwell times and/or
> vacuum extraction or other mechanical means. This is inevitable. OK, one
> well constructed machine produces a kg or so of losses per year and
> isn't going to make much difference to the climate change caused by the
> teragrams of CO2 emitted by us annually, nor is it likely to be
> restricting to lose a few hundred dollars-worth of the stuff. If, as has
> been suggested, every assembly plant in the world had one, then we are
> talking about hundreds of thousands of such machines, some of them cheap
> and highly emissive, spewing out an aggregate of many tonnes of the
> substances each year. It is conceivable that this would overtake CO2 as
> the chief cause of the greenhouse effect, because the atmospheric
> residence time of CO2 is of the order of a hundredth that of the PFCs
> and is more easily sequestered, being ionically active in the presence
> of water vapour.
>
> I therefore dispute, in the strongest possible terms, the contention
> that vapour-phase soldering should be allowed to proliferate. Rather, it
> would be wise to avoid it.
>
> There is also a political aspect to the question. As we have seen at
> Doha recently, there is discord as to how to handle greenhouse gas
> emissions. It is probable that we are at a turning point and that, in a
> year or two, the nations will agree that something must be done to
> reduce GG emissions. This will involve increasing regulation. CO2 will
> be difficult to regulate but PFCs will be easy, just as the Montreal
> Protocol regulated CFCs. I foresee that PFCs could be phased out from
> manufacture over, say, a five or ten year period, at the end of which
> all the VP reflow machines will be worth only their scrap metal value.
>
> Brian
>
> On 07/12/2012 03:03, Bev Christian wrote:
> > "No self-respecting electronics manufacturer should be without a
> vapor-phase
> > soldering machine in the facility."
> >
> > Sorry, I cannot agree.  We tried one and then sent it back. We have a
> ton of
> > RF cans with small holes in them for underfill application.  The heat
> > transfer liquid condensed inside the cans and we couldn't get it out. It
> > was still there days, probably weeks later and as has already been noted
> the
> > stuff is expensive.  And how many of the liquids being used are still
> > incredibly excellent global warmers? I haven't looked at their tech
> sheets
> > lately.
> > Bev
> >
> >
> >
> > -----Original Message-----
> > From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
> > Sent: Thursday, December 06, 2012 7:38 AM
> > To: [log in to unmask]
> > Subject: Re: [TN] Termination finishes, Cu thickness under Ag, Au-Pt-Pd
> >
> > We have two vapor-phase reflow machines here at GD, and I work with VPS
> at
> > other companies in the area. The ones we use are from R&D.
> > http://www.rdtechnicalservices.com/System-RD2.cfm
> > We have an RD-1 and an RD-2, and I am supporting the installation of an
> > RD-52 at another site, and have used all three machines at various
> > companies.
> >
> > No self-respecting electronics manufacturer should be without a
> vapor-phase
> > soldering machine in the facility.
> >
> > For high-mass, difficult-to-solder assemblies, VPS just cannot be beat.
> VPS
> > is also an excellent method for performing some of the more advanced
> > processes such as compliant lead attachment, BGA reballing, CSP and
> flipchip
> > reflow, etc. At one location we set up a really good process for
> > manufacturing PoP components, including the die-attach where the
> die-bond
> > epoxy is cured at the same time the die is soldered. Having an
> oxygen-free
> > atmosphere really helps.
> >
> > Also, I have found R&D to be a really good company, and the owner is a
> real
> > square shooter. They have great VPS machines and good service. I don't
> have
> > any experience with other VPS systems, so I cannot comment on that. I
> have
> > no financial interest in R&D, just a lot of good experience.
> >
> > As with any VPS, proper maintenance is required. With condensation
> soldering
> > you will get a buildup of flux on the inside of the machine and it must
> be
> > kept clean. I strictly enforce a monthly maintenance program, and if
> done
> > diligently the machines will last a long, long time. For the larger VPS
> > systems a small chiller is usually required, so keep that in mind when
> > considering purchasing a system.
> >
> > -----Original Message-----
> > From: TechNet [mailto:[log in to unmask]] On Behalf Of Robert Kondner
> > Sent: Wednesday, December 05, 2012 2:37 PM
> > To: [log in to unmask]
> > Subject: Re: [TN] Termination finishes, Cu thickness under Ag, Au-Pt-Pd
> >
> > Inge,
> >
> >   On the VPSsubject  your comments echo what I have heard.
> >
> >   Did you get some actual hands on time for experimentation? If so what
> > machine?
> >
> > Thanks,
> > Bob K.
> >
> > -----Original Message-----
> > From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
> > Sent: Wednesday, December 05, 2012 3:09 PM
> > To: [log in to unmask]
> > Subject: Re: [TN] Termination finishes, Cu thickness under Ag, Au-Pt-Pd
> >
> > Hi Inge!
> >
> > Welcome back ol' buddy! I for one, have missed you here! Wish we could
> get
> > Paul to drop in once in a while. But I know that will be unlikely.
> >
> > Me a bagpipe blower? You have got to be kidding me! I don't even know
> how to
> > hold one of them things much less play one! They look kinda' creepy to
> > me...like an octopus or something. But when I hear "Amazing Grace" being
> > played on bagpipes, my heart pounds and I get goose bumps.
> >
> > I've not faded away, I'm still here, just don't have as much to talk
> about
> > as I used to. Anyways, this group has never been about any one person,
> it's
> > always been about all of us. Some have been here longer than others, but
> > what has made this email forum as solid and long lasting as it has been,
> has
> > been the contributions from everyone in this group. I hope that this
> will
> > continue.
> >
> > I'm dealing with what I guess you could call a "speed-bump" in my life's
> > road right now, but I plan on being here for a long time...
> >
> > Again, welcome back!
> >
> > Steve
> >
> > -----Original Message-----
> > From: Inge Hernefjord
> > Sent: Wednesday, December 05, 2012 11:55 AM
> > To: [log in to unmask]
> > Subject: Re: [TN] Termination finishes, Cu thickness under Ag, Au-Pt-Pd
> >
> > Hi Wayne & collegues,
> >
> > heard from Joyce that you missed my comments. Sorry for that. When Steve
> > Gregory faded away as kind of bagpipe blower in the TN brigade, I lost
> some
> > contact with the troops march and became last one and with time I saw
> the
> > troops at distance. Well, with  my old legs, seems as I have to get lift
> > with a jeep and catch up with you.
> >
> > On the theme you just discuss with Julie, I'd say to her not to mix with
> > changing the component finish immediately. Doing such things can end in
> a
> > never-ending-process. I am not updated with what is actually going on,
> so my
> > advice may not be of any help, but there is one soldering method that
> have a
> > very generous process window and that is VPS, Vapour Phase Soldering. It
> has
> > some very attractive advantages, like instant and simultaneous heating,
> > extremly low Oxygen presence and is very fast. All properties that makes
> > even many poor weldable>acceptable weldable. You may not be able to try
> > this, of some reason. Just wanted to put up a finger and feel the wind
> > direction
> >
> > Inge
> >
> > On 5 December 2012 00:41, Thayer, Wayne - IS
> > <[log in to unmask]>wrote:
> >
> >> Hi Julie-
> >>
> >> Sorry for the late response.  I have a lot of experience with this or
> >> similar material.  Yes, burnishing helps.  I also deliberately use an
> >> iron tip that doesn't wet well.  Paste with SMT works too, and is more
> >> controllable.  We typically used the SnPbAg alloy with about 2%Ag, but
> >> I don't know if that helped.  Our rule of thumb was you got three
> >> shots to solder to it, IF you used pre-heat and were very careful.
> >> BUT, this product is cake to solder to compared with AgPd, which most
> >> of the thick film commercial products used.  That stuff would only
> >> survive a very carefully controlled single reflow.
> >>
> >> One thing we learned is that the leach rate SKYROCKETS if the designer
> >> put the PtPdAu directly on top of thick film Au where the solder was
> >> going to be.  That recipe leaches just as bad as plain gold.  The
> >> overlap MUST be behind a solder dam.  (The thick film vendors only
> >> tell you this AFTER you figure it out on your own!)  By the way, plain
> >> gold solders just fine on ceramic using SnAu eutectic solder.  It is
> >> very expensive and is quite hot (270C or so).  The joints are very
> >> pretty
> > shiny silver and very strong.
> >>   You can also weld copper wires to thick film gold or silver.
> >> MiniCircuits
> >> sells piles of RF parts containing tiny transformers attached this
> >> way, and this technique is also used on RF inductors which are wound
> >> on an alumina mandrel.
> >>
> >> We ended up having a low temperature copper put on top of the gold
> >> whenever we could.  It is much more robust--still wets horribly though!
> >>
> >> Wayne Thayer
> >>
> >> -----Original Message-----
> >> From: TechNet [mailto:[log in to unmask]] On Behalf Of Steven Creswick
> >> Sent: Wednesday, November 28, 2012 8:59 AM
> >> To: [log in to unmask]
> >> Subject: Re: [TN] Termination finishes, Cu thickness under Ag,
> >> Au-Pt-Pd
> >>
> >> Julie,
> >>
> >> Yes, the addition of a small amount of Pt does slow up the rate of the
> >> conductors leaching into the solder.  From practical experience, the
> >> more Pt is added, the better the leach resistance.  However, the more
> >> Pt is added, the greater are wetting problems.
> >>
> >> Thick film ink suppliers [used to] offer inks with different amounts
> >> of Pt so you could slightly 'chose your poison.'
> >>
> >> Also can depend on whether it is a fritted, or a frit-less, system.
> >>
> >> Like Mike says - BURNISH before solder IS the general rule!
> >>
> >> Never was something you really 'wanted' to solder to, unless you had
> >> no other choice.
> >>
> >>
> >> Steve Creswick
> >> Sr Associate - Balanced Enterprise Solutions
> >> http://www.linkedin.com/in/stevencreswick
> >>                           616 834 1883
> >>
> >>
> >>
> >> -----Original Message-----
> >> From: TechNet [mailto:[log in to unmask]] On Behalf Of Julie Silk
> >> Sent: Tuesday, November 27, 2012 8:02 PM
> >> To: [log in to unmask]
> >> Subject: Re: [TN] Termination finishes, Cu thickness under Ag,
> >> Au-Pt-Pd
> >>
> >> The claim of the supplier is that the Pt prevents the Au from
> >> dissolving into the solder.  Hmmm.  Can anyone back that up?
> >> The recent info on this is that it's looking like a wettability
> >> problem more than a dissolving-into-the-joint problem, although
> >> neither is confirmed.
> >>
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