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November 2007

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Subject:
From:
Jack Olson <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Jack Olson <[log in to unmask]>
Date:
Fri, 2 Nov 2007 10:06:45 -0500
Content-Type:
text/plain
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text/plain (91 lines)
OK, I didn't get much response to my "informal poll"
(thanks Dewey and Werner!),
so I'll ask one more specific question before I start getting grouchy
(grin)

If you attend Lead Free Reliability presentations by people like
Werner Englemaier or Gary Ferrari (highly respected in our industry)
they recommend a material like IPC-4101/126 or /129

If you go to websites like Merix (also highly respected)
http://www.merix.com/RoHS+_+Lead+Free.aspx?id=4
they recommend something different

(so don't say, "ask your fabricator")

Does anyone have knowledge that would help clarify the discrepancy?
Is the /126 /129 just SUPER reliable over /99 and /124?
(ok, that was more than one question)
we are auomotive, but I know I am going to be asked to justify
the added expense sooner or later...
maybe I'm just looking for a group hug.
sheep mentality.
baaa....

and no, I'm not a materials expert, but I MUST call out SOMETHING.
and SOON!
(I'm trying to wade through the materials info in the new Printed
Circuits Handbook, but its still confusing.
But hey, maybe I WILL be a materials expert by next week, huh?)

onward thru the fog,
Jbro


On 10/29/07, Whittaker, Dewey (EHCOE) <[log in to unmask]> wrote:
>
> Yes and a few additional requirements.
> Yes and /129 also.
> It depends (cha-ching).
> Yes.
> Yes.
> 1.5 mil avg. with 1.2 mil minimum.
>
> Dewey
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Jack Olson
> Sent: Monday, October 29, 2007 10:28 AM
> To: [log in to unmask]
> Subject: [TN] Bare-Board Materials for Lead-Free Soldering
>
> I'm hoping to get an informal poll of fabricators and people who specify
> bare board materials.
>
> There's been a lot of literature and presentations lately that
> recommend numbers for better material performance under the higher
> soldering
> temperatures.
>
> IPC-4101/126
> Tg=170 or higher
> Td=340 or higher
> maximum expansion 3%
> etc.
>
> I'm not questioning the wisdom of the numbers, I'd just like to know
> whether
> everyone (who is doing lead free soldering) is really USING these
> numbers?
> Or this material? Is there no wiggle room anymore? (EVERY example I see
> now,
> lists /126 material)
>
> I've also been advised to use a thicker minimum hole wall thickness than
> before. Is that common now? >1mil?
>
> thanks,
> Jack
>
>

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