Thanks Lynn,
I stand corrected on the race. I was just passing a few comments based on
talking with a couple of aerospace gentlemen (US) and a couple of automotive
development engineers (European) on what they wanted. When I get told to
make a lead-free product for a customer I ask which alloy, then do it. The
pace at which I'm expected to do it makes me think of running a race.
I fully agree with your reliability statement, from your description I guess
I've seen tests and results indicating the same or similar. I think I stated
that was my concern when replying to Harvey.
I know of a lot of money is being spent to find a more reliable alloy than
the tin lead variants currently in use in autos. I don't believe anyone
involved in the project has a throbbing desire to be lead-free, however the
companies involved have seen reliability data indicating improved
performance over the norm and have taken advantage of funding to pursue
performance improvement research within (some fairly exotic) lead-free
compositions. Personally speaking, from talking with my metallurgist
colleagues, I don't think the exotic multi-element alloy routes will be
successful, very interesting but not commercially successful. Not that I
prejudge the physical performance of that type of alloy, I just don't
believe the manufacturing capability exists to manufacture such alloys to
within the - potential - limits required, it's difficult enough maintaining
63/37, 62/36/2 is almost controllable.
You state the markets are driving the changes, I think you may be the first
to have made that statement - congrats if you are.
Is that market forces from the perspective of lead-free, i.e. 'green', or
from performance 'improvements' or something else?
While I'm here, on another cobweb dusted from the recesses of my mind, it
was interesting (to me) that Jim Smith when chastising me this afternoon
pointed out the history of tin lead alloys and the comfort in having the
knowledge of the alloys etc.... (my apologies if I don't have the quote
exactly correct). However the point being that if you were to be a fly on
the wall in an alloy manufacturing plant or their service/development lab I
think you'd find that all is not as clear cut nor as stable as can be made
out superficially. I know that it wasn't clear cut in the plants that I
worked in. I spent a lot of time making products work in spite of the
'historically' well known tin lead alloy. It was always helpful to have a
metallurgist around who could go back twenty or thirty years to remember why
the spec was changed, then changed back, then why/when element 'B' was added
to improve performance 'C', then why it was taken out again as the flavor
changed.
If anybody wants to know which plants, contact me offline - I wont tell you,
but contact me anyway.
Sorry to ramble but I've nothing else in life.
Best regards,
Andrew Hoggan
BBA Associates Ltd
www.bba-associates.com
'stop the legislation'
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]]On Behalf Of Lynn Norman
Sent: 01 August 2001 17:25
To: [log in to unmask]
Subject: Re: [LF] Eutectic alloys?????
Both aerospace and automotive companies are running to embrace lead-free
technology on the basis that it could get them out of this thermal
management bind. Ford have already made the jump.
Working in the automotive electronic industry, I can tell you that we AREN'T
"running to embrace lead-free". On the contrary we are against it. The
main reason we're evaluating lead-free is purely market driven. We have
test data that shows the SAC alloy is much less reliable at high (underhood)
temperatures and with longer dwell times. We won't start manufacturing
modules for underhood applications with lead-free until we are forced to.
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