[tinwhiskers] Re: Reliability Concerns with the Use of Lead (Pb) Free Solder in Telecommunications Products
- From: "Meschter, Stephan J \(US SSA\)" <stephan.j.meschter@xxxxxxxxxxxxxx>
- To: <tinwhiskers@xxxxxxxxxxxxx>
- Date: Wed, 6 Aug 2008 13:17:01 -0400
What is the date of this notice?
Steph
_____
From: tinwhiskers-bounce@xxxxxxxxxxxxx
[mailto:tinwhiskers-bounce@xxxxxxxxxxxxx] On Behalf Of Bob Landman
Sent: Wednesday, August 06, 2008 12:09 PM
To: 'tin whiskers forum'
Subject: [tinwhiskers] Reliability Concerns with the Use of Lead (Pb)
Free Solder in Telecommunications Products
http://www.telcordia.com/services/genericreq/digest/notices.html
Notices to the Industry
* Reliability Concerns With the Use of Lead (Pb) Free Solder in
Telecommunications Products
<http://www.telcordia.com/services/genericreq/digest/notices.html#leadfr
ee>
_____
Reliability Concerns with the Use of Lead (Pb) Free Solder in
Telecommunications Products
The European Union "Restriction of the use of certain hazardous
substances in electrical and electronic equipment" was put into effect
in July 2006. Known as the RoHS Directive, this legislation bans placing
on the EU market new electronic equipment containing more than
agreed-upon limits of certain chemicals that are perceived as hazardous
in the manufacture, use, or disposition of products. These restricted
substances include:
* Cadmium
* Mercury
* Hexavalent Chromium
* Brominated Fluorocarbons
* Polybrominated biphenyl (PBB) and polybrominated diphenyl ether
(PBDE) flame retardants
* Lead.
The RoHS directive currently applies within the EU. Other countries are
considering similar restrictions as are some states within the U.S. Most
telecommunications equipment suppliers are designing and building
electronic products to suit the world market. As a result, many
geographic markets are receiving products that have been made in
accordance with the RoHS directive, even where not required locally. It
is not an attractive economic option to design and manufacture one
product for the EU and a slightly different product for non-RoHS
markets.
Included in the RoHS legislation is a ban on the use of lead (Pb) in
solder. Lead has been added to tin for use in soldering electronic
assemblies for 50 years or more and has the following benefits:
* Low melting point
* Good wetting characteristics for better solder adhesion
* Good ductility for resistance to stress and strain
* Reduction of the growth of tin whiskers
* Excellent overall reliability of the solder joint.
As a contrast, most lead-free solder alternatives that have been
examined at this time have:
* Higher melting points resulting in more difficult processing
* Poor wetting characteristics and increased joint failures
* Reduced ductility making assemblies vulnerable to vibration and
thermal stress
* Undetermined ability to mitigate tin whiskers
* Unknown reliability in telecommunications environments.
In short, the lead-free solder alternatives have not demonstrated
suitability or reliability in the telecommunications market. For this
reason, the RoHS legislation includes an exemption that allows for the
continued use of lead in solder for telecommunications and data server
products until at least 2010.
Despite the exemption, the continued availability of parts compatible
with lead solder fabrication is a concern. In order to provide
economical products, telecommunications suppliers use many electronic
devices shared across multiple industries. Not all industries share the
lead-solder exemption. For this reason, some widely used devices such as
memory are now being made almost exclusively for lead-free soldering. In
this form, the parts may be incompatible with leaded soldering and may
be ill suited for telecommunications equipment applications.
In order to maintain high and predictable network reliability, it is the
expressed desire of the major telecommunications carriers within the
United States, as well as Telcordia, that:
1. Telecommunications equipment manufacturers shall continue to use
leaded-solder until alternatives have demonstrated reliability suitable
for telecommunications infrastructure, and
2. Component suppliers shall continue to make available components
compatible with leaded-solder manufacturing until alternatives have
demonstrated reliability suitable for telecommunications infrastructure.
It is anticipated that this position will be reflected in the next issue
of GR-78, Generic Requirements for the Physical Design and Manufacture
of Telecommunications Products and Equipment.
For further discussion, please contact Richard Kluge, Telcordia Director
- NEBS(tm) Technical Services, at rkluge@xxxxxxxxxxxxx or +
1.732.699.5490.
Other related posts:
