Gaby,
I share with your view regarding the leadfree transition. When politics and marketing mixed with science, everything is become "faith initiative"...It will take time for good come out to be the true winner... the only problem is the "weed out" process is got be a bit longer (most of the study is "focused" only on very narrow field: leadfree with ignore the waste stream, lab reliability with ideal package (all no lead), but ignore the transition and device finishing limitation (someoone forgot how many devices make a system)...etc.etc.
Well, is anyone developed brittle transition temperature of the leadfree alloy yet? It is bitterly cold here...what is the impact resistance...just kidding.
(it over my brittle bone transition here for -23 C this morning...not sure about the impact resistance...got be low when I fall)...
jk ;-)
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Gabriela Bogdan
Sent: Friday, January 21, 2005 11:12 AM
To: [log in to unmask]
Subject: Re: [TN] Lead-free Wave Solder Pot Impurity Levels
Dear friends!
With the overwhelming amount of information about disinformation concerning
leadfree, I am ashamed to confess that I lost my way.
I try to be GOOD, but I don't know anymore what it means concerning this
subject.Once we had clear instructions, and I was GOOD following them. Today
we have so much "IF"s, "BUT"s, and "MAYBE"s concerning reliability, who is
responsible-for what-, and so on.
Soon we will shift to leadfree. We will give the consumers what we are asked
for. But is our conscience at peace?
I just can not understand how and why rules are imposed before the solution
to all the problems are found, and if not, openly stated as being there and
brought to the knowledge of the customers and consumers.
I would like to know at least how and according to what one will be
qualified for leadfree products beside the requirements for the materials.
Will the reliability tests remain the same for the future products as they
were until now for lead containing products?
Gaby
----- Original Message -----
From: "David D. Hillman" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, January 21, 2005 3:40 PM
Subject: Re: [TN] Lead-free Wave Solder Pot Impurity Levels
> Hi Leland! Unfortunately the industry is going to need some time to
develop
> the wave solder pot impurity level table you are seeking. A fair portion
of
> the industry is using the current JSTD-001 impurity level table (user
> modified for the increased tin, silver, and copper levels) and closely
> monitoring their impurity levels. I would recommend that you work closely
> with your solder supplier as they have visibility into the status/trends
of
> existing wave solder processes to whom they supply solder. Here is a
> relevant reference on some wave solder impurity levels that may be of
> interest:
>
> “Development and Validation of LeadFree Wave Soldering Process”, A.
Forsten
> etal, Soldering & Surface Mount Technology, Vol. 12, No. 3, 2000
>
> The short term solution is that the industry just needs time to understand
> the potential changes to the JSTD-001 impurity limits that Pbfree solder
> usage may induce. Good Luck.
>
> Dave Hillman
> Rockwell Collins
> [log in to unmask]
>
>
>
>
>
> Leland Woodall
> <lwoodall@CSTECH-
> INC.COM> To
> Sent by: TechNet [log in to unmask]
> <[log in to unmask]> cc
>
> Subject
> 01/21/2005 05:26 [TN] Lead-free Wave Solder Pot
> AM Impurity Levels
>
>
> Please respond to
> TechNet E-Mail
> Forum
> <[log in to unmask]>
> ; Please respond
> to
> Leland Woodall
> <lwoodall@CSTECH-
> INC.COM>
>
>
>
>
>
>
> Hi Folks,
>
> I have a small dilemma here. There is a standard for eutectic solder pot
> impurity levels, but I can't seem to find one for lead-free. Is there
> such an animal?
>
> Everything I've researched on the Web shows only recommendations, namely
> from Alpha and AIM. Those two have slight disagreements.
>
> At least they provide something, and that is impressive.
>
> It also appears that the major concern is processing problems versus
> product reliability. If copper content gets too high, the wave solder
> viscosity becomes too high and bogs down the mechanical parts of the
> machine.
>
> When things get out of whack, can I expect reliability problems as well?
>
> What levels of impurities would cause premature joint failure,
> specifically?
>
> Are we too new to this, and have tests not yet been agreed upon? Is IPC
> addressing the issue?
>
> Any help you could provide would be sincerely appreciated.
>
> Offline comments are welcomed.
>
> Many, many thanks,
>
> Leland Woodall
> Quality Coordinator
>
> Keihin Carolina System Technology, Inc.
>
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