http://www.aimsolder.com/techarticles/A%20Study%20of%20Lead-Free%20Solder%20
Alloys.pdf
I found this article on CASTIN lead-free soldering alloy...
CASTIN is a combination of copper, antimony, silver and tin. The
nominal composition is 96.2% tin, 2.5% silver, .8% copper and .5% antimony.
It's supposed to be very close in performance to 63/37 tin/lead solder.
They even say it can be used to wave solder. Interesting.
Bill Brooks
PCB Design Engineer , C.I.D., C.I.I.
Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510
http://pcbwizards.com
-----Original Message-----
From: [log in to unmask]
[mailto:[log in to unmask]]
Sent: Wednesday, June 16, 2004 11:05 AM
To: [log in to unmask]; [log in to unmask]
Subject: RE: [DC] Lead free processes and the impact to your PCB manufactu
ring and assembly
We are finding real problems with parts procurement, and have found that
roadmaps of some of our parts suppliers is to phase out lead terminated
parts fairly rapidly. We also don't know the impact yet, but are watching
the situation since some of the termination chemistries are not very
compatible with the normal PbSn chemistries.
The main issue we have found is the higher soldering temperature. We don't
have enough data yet to verify reliability problems due to the changes in
solder fillets, but it is a possibility pad sizes will have to increase
because of it, and because of the centering and tombstoning that is more
prevalent. We have also found some differences in electrical
characteristics of High-frequency RF boards that have necessitated changes
in circuit values and re-layout of critical circuits, mainly in areas free
of soldermask.
My information is second hand, I am not on the core team so I don't have
details.
A LOT of designers have their collective heads in the sand about this. When
the PNW chapter polled for what members and associates wanted to hear about
this year, lead-free was last or second-from-last thing on the list.
--
George Patrick
Tektronix, Inc.
Central Engineering, PCB Design Group
P.O. Box 500, M/S 39-512
Beaverton, OR 97077-0001
Phone: 503-627-5272 Fax: 503-627-5587
http://www.tektronix.com http://www.pcb-designer.com
It's my opinion, not Tektronix'
-----Original Message-----
From: Brooks,Bill [mailto:[log in to unmask]]
Sent: Wednesday, June 16, 2004 10:11
To: [log in to unmask]
Subject: [DC] Lead free processes and the impact to your PCB manufacturing
and assembly
Yesterday I was reading the cover article in Electronic Design on
"Managing Product Obsolescence" page 47 by Ron Schneiderman and it alarmed
me so that I fired off an e-mail to my boss in engineering and the heads of
the company manufacturing group. It seems we can't ignore the changes in the
industry or procrastinate and keep using tin/lead solder if the component
manufacturers are going all lead free... (unless the components they make
are compatible with both processes.) That I have not looked into as yet, but
I can assure you, I will be learning more about the lead free process and
what the potential impacts will be on our ability to produce our products.
Until now, I have been sitting on the sidelines listening in occasionally to
issues on the lead free debate... I didn't think it would affect us
directly, but now it looks like I am forced to really pay attention to it
because it will most likely affect us all.
I would be grateful if you have had experience with the lead free
manufacturing process and its impacts at your company and would like to know
how you dealt with it... I want to capture a list of potential needed
adjustments to our processes and designs that we should be looking into
changing and help to get us on that path so we can prevent any potential
manufacturing/rework issues in advance.
Here's what I wrote:
-------------------------------
Greetings -
There has been much discussion in the IPC and in the electronics
manufacturing news circuit on the 'lead free' mandate that the E.U. authored
years back... We will be seeing the effects of it coming to a head in the
very near future, if it has not already begun to affect us by now.
If electronics parts manufacturers are moving to lead free compatible
components at the rates suggested in the news we are in for more parts
obsolescence issues and in larger quantities than we have seen before. Ref
Electronic Design magazine cover article "Managing Product Obsolescence"
June 7,th 2004.
We would be prudent to study the impact of lead free technology on our
compliment of components and make sure we head off this potential design and
manufacturing procurement bottleneck before it rears its ugly head in the
middle of production of a large order. (I would suspect that there has
already discussion about this at higher levels... )
Even if we say that we might be exempt from using lead free processes in our
products as I have heard some military suppliers say, we may find that we
cannot get the parts that would work with a tin/lead soldering process after
a few years... They are going to decline out of demand and that will drive
them into obsolescence. The only people with lead process parts in stock
will be the scalpers and higher priced component brokers. I would expect
there to be exceptions to the rule but we need to identify the potential
problems before they get to be problems.
PCNalert, a company that monitors and reports on parts obsolescence issues,
is receiving 50 parts obsolescence notices a day now. That trend will most
likely get worse before it gets better.
If we do decide to go lead free in our processes we will need equipment that
can support the soldering temp profiles and higher temp materials will be
required for boards. This may also affect the footprint patterns for many
parts as well. I'm sure there will be other impacts, supplies of lead free
solder for rework, higher temp soldering irons, fluxes with different
chemistries, potential safety issues, training to deal with newer
technologies... the list may be long...
The deadline for compliance with the E.U. hazardous substance mandate is
2006. We will probably see common lead containing components drop off in
availability before then as the lead free counterparts are becoming more and
more available.
I just wanted to bring it to your attention if you had not thought of the
potential impacts on your department or specific activities here at Datron.
Best regards,
Bill Brooks
PCB Design Engineer , C.I.D., C.I.I.
Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510
http://pcbwizards.com
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