Hi folks! I have been sitting on my hands long enough (which makes having
my morning Coke a chore anyway)! I believe that folks are overlooking the
long term picture. The favored Pbfree alloys are tin based and molten tin
is a reasonably corrosive metal. Jack mentioned the upcoming APEX paper on
the impact of Pbfree alloys on the wave soldering operation but there are
other areas of concern. Soldering iron tips will degrade faster due to the
increased tin percentage in the solder alloys. Reflow systems will be
required to undergo increased preventative maintenance schedules as blower
motors and lubrication points will undergo faster degradation. The
temperature increase combine with the increased attack of molten tin will
add cost to our soldering processes. Will the equipment manufacturers
create solutions to remedy these issues? Absolutely but it would be a naive
thought process to assume that our current assumptions on equipment wearout
will continue to be valid and the cost impact changing to a Pbfree solder
process will be minimal.
Dave Hillman
Rockwell Collins
[log in to unmask]
Peter Lymn
<[log in to unmask] To: [log in to unmask]
COM> cc:
Sent by: Leadfree Subject: Re: [LF] Equipment changes needed for lead-free
<[log in to unmask]
>
03/14/2003 05:57
AM
Please respond to
"(Leadfree
Electronics
Assembly Forum)";
Please respond to
Peter Lymn
Eric, you asked...
1. For PWB manufacturing, making boards that stand up to higher
temperatures
apparently requires some change in materials, no? Does any equipment need
to
be replaced to make these modified boards?
Our experience is that standard materials are no problem apart from CEM1.
We have conducted most of our 'lead free' Hot Air Solder leveling testing
and customer trials on our standard 'Vertical' leveler with good results.
Most of the work we have done has been with the SnCu and recently SnCu with
Ni as both are compatible with all the proposed lead free alloys as well as
conventional SnPb alloys. The Nickel addition results in an apparently
brighter and less crystalline appearance on large copper areas. I can
confirm that we were able to obtain comparable results at lower
temperatures
with the Nickel addition although it is our preference to use higher
temperatures and gain the improved appearance. That said, the optimum
results have been from the horizontal machines which provide much greater
control over thickness and uniformity than vertical systems generally, but
the forced convection pre-heat, followed by the short solder contact time
(less than a second) helps considerably.
We have two vertical machines set up for sample testing should anyone be
interested. One is currently filled with SnCu and another with SnCu+Ni and
we are considering setting up a third with SnAgCu. We conduct solder alloy
testing during the 'run up' of newly completed horizontal machines and the
service centre in Scotland has ordered a horizontal machine designed
specifically for lead free solders in anticipation of the change over.
Please feel free to contact me offline for machine setting parameters etc.
-----Original Message-----
From: Eric Williams [mailto:[log in to unmask]]
Sent: 10 March 2003 02:58 AM
To: [log in to unmask]
Subject: [LF] Equipment changes needed for lead-free
Hello,
I am trying to find out more about what equipment changes are needed to
switch board manufacturing and assembly facilities to lead-free. I am
trying
to get an idea of how difficult making the change would be for small and
medium size firms in terms of investment in new equipment. The answer no
doubt depends on what alternative is being used but I would very much
appreciate hearing from people in the group about what they have heard/read
about the different options.
1. For PWB manufacturing, making boards that stand up to higher
temperatures
apparently requires some change in materials, no? Does any equipment need
to
be replaced to make these modified boards?
2. For PWB assembly, one could break down the process flow into printing,
placement, reflow/wave, inspection. On the lead-free website, Brian Bauer
and Angela Grusd hint that for Su/Ag/Cu solder, inspection may be most
affected (needing new equipment?). Harvey Miller, a member of the list,
makes an estimate of capital costs assuming that only reflow/wave ovens
will
need to be replaced. A source in the Taiwanese electronics industry
suggests
that the lead-free switch is really only about materials and that no
equipment needs to be changed. As far as I have found so far, no one is
suggesting that the printing and placement machines need changing.
According
to your experiences/knowledge, what equipment needs to be replaced? Are
there written analyses of this issue?
Thanks very much.
Best Regards, Eric
---------------------------------------------------------------------
Eric Williams
United Nations University
Environment and Sustainable Development Programme
IT and Environment Project
http://www.it-environment.org
53-70 Jingumae 5-chome Shibuya-ku Tokyo, Japan
Phone: 81-3-5467-1352 Fax: 81-3-3406-7346
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