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45031
RoHS compliant tin/lead plating
[Ohio]
May 7, 2007
Is tin/lead plating (maximum 97% tin and 3% minimum lead) RoHS
compliant?
Jim Dawson
plating & finishing is a process within our manufacturing
facility - Cincinnati, OH, USA
May 22, 2007
I'm working very hard on understanding this. I'm still not there.
I see your letter has gone unanswered for a while, so I'll run this
up the flagpole...and see who shoots it full of holes. Take what I
say with a grain of salt.
The rule is, as far as I can understand, that not more than 0.1% of
any "homogenous" part can consist of lead. A plated coating is not
considered "homogenous" in that it's not something you can unscrew -
it's part of the metal.
So, I suppose you would determine the thickness of the coating, the
density of the alloy, then, the surface area of the part. Now, you
have the weight of the coating...multiply by 0.03, now, you have the
weight of the lead.
Now, weigh the whole component, and divide the weight of the lead by
that weight. If the number is less than 0.001, it's compliant. If
it's greater, it's not. That is what I think it all means,
anyway.
There are numerous exemptions. They are also still arguing about
what's "homogenous."
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Dave Wichern
- Bronx, NY, USA
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May 25, 2007
Dave, that seems a long way of saying 3% lead exceeds 0.1% lead so
non-RoHS.
Jim, there are exemptions to the 0.1% lead limit, but probably none
applies. See the Global Automotive Declarable Substance List (GADSL),
which includes both RoHS & ELV, at http://www.gadsl.org
Exemptions include free-machining alloys and critical electronics
applications in aerospace and computers. Some exemptions are being
phased out as replacements are developed. Intel uses a 5% Pb solder
on present CPU chips but has announced next generation, 0.45 nm chips
will use a new, Pb-free solder.
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Ken Vlach
- Goleta, California
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May 29, 2007
Not only was it long, Ken, it was wrong.
Apparently plated coatings are considered to be a "homogenous" part,
because they can be physically separated from the substrate. So, the
answer to the original posters question is pretty definately 'no',
unless it falls under one of those exemptions
Dave Wichern
- Bronx, NY, USA


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