We use two VPs, a small one with an 'elevator' for hybrids and
microelectonic parts in general, and a big in-line machine for all kind of
boards, the largest being 600 millimeters. We appreciate these both for the
inert atmosphere and ability to heat all components simultaneously
independent of their color or structure. Another plus is the absence of
white residues after the soldering. Also, boards with extreme and odd
components like transformers, superBGAs, power connectors etc be given the
optimal heat curve, which was hard to obtain with the ovens. Cleaning from
flux is not a problem, as the bottom section is sucked for contamination by
means of a valve that opens and pumps out liquid to a waste tank. The
machine allows manual placing of complex structures if these cannot travel
on the conveyor. The machine startup time is shorter than for the ovens,
which need pretty long time to swing to a steady condition, because with VP
you can apply immense lot of power : the liquid can just boil and generate
vapour, can't be overheated. In the whole, we are satisfied with the 'sauna'
as some name it.
Inge
----- Original Message -----
From: "Stadem, Richard D." <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, October 15, 2008 8:37 AM
Subject: [TN] FW: [LF] Vapor Phase Soldering
-----Original Message-----
From: Stadem, Richard D.
Sent: Wednesday, October 15, 2008 10:34 AM
To: '(Leadfree Electronics Assembly Forum)'; 'Tony Ingano'
Subject: RE: [LF] Vapor Phase Soldering
We use VP soldering for reflow of massive or troublesome assemblies or
when doing certain subassembly processes (socket manufacturing, etc.)
They are an invaluable tool in any manufacturing facility. There are no
process drawbacks with using the modern VPS machines, better preheaters
and sumps fixed the issues of thermal shock and excessive vapor fluid
use. 3M's Fluorinert and Galden PFPE fluids are safe to use from an
environmental standpoint, per our PCA state offices.
You must recognize that VPS requires some amount of thermal shock in
order to facilitate the condensation action, but it is not usually so
large as to hurt the reliability of most standard SMT components. There
may be some heat-sensitive components that you would not want to solder
with VPS, however. You need to do the homework before jumping in and
running production hardware with VP. Homework is spelled
q-u-a-l-i-f-i-c-a-t-i-o-n, which should include thermal cycling.
But we get a lower DPMO when using VPS than we do with convection reflow
ovens. Better heat transfer = better solder wetting.
We use R&D Technical Services machines, Model RD1 and RD2, and they have
worked extremely well for us. Find them at:
http://www.rdtechnicalservices.com/index.html
Disadvantages are the cost of the fluids, and the machines require more
cleaning (maintenance) due to the amounts of flux contamination on the
insides of the chamber from the vapor. We have our maintenance people
thoroughly clean them each month as a means of preventing oxidation of
the internal chamber parts.
We use two temperatures of fluid, depending on the application. I am
still waiting for Galden and 3M to get schmart and provide the different
fluid tempertures in different colors so it is easier to avoid using the
wrong temperature fluid.
Anyone know of an inert dye that I can add to the fluid that would not
affect its performance?
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of Tony Ingano
Sent: Wednesday, October 15, 2008 8:14 AM
To: [log in to unmask]
Subject: [LF] Vapor Phase Soldering
I am wondering if anyone is currently using vapor phase soldering. What
are the disadvantages of vp soldering? Also, who are the major
manufacturers of VP soldering machines?
Thanks,
Tony
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