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The
electronics industry is migrating to lead-free electronics, both
to comply with government legislations and to increase market share
through product differentiation. Considering that lead-based electronics
have been in use for over 40 years, the adoption of lead-free technology
represents a dramatic change. The manufacturing of lead-free electronic
products involves assembling lead-free components to lead-free printed
circuit boards using lead-free solder alloys. Key issues that are
being addressed by academia and industry include lead-free solder
alloy selection, characterization of lead-free solder alloy properties
and behavior under various stress loading conditions, lead-free
manufacturing, logistics and intellectual property issues, and lead-free
assembly reliability assessment.
Since February 13, 2003, lead-free has been a law in EU (European
Union). The implementation date is July 1, 2006. That means,
after July 1st, all the electronic products (except those with exemptions)
cannot be made in and shipped to EU.
The move towards lead free has been a topic circulating within the
industry for a number of years now and the major driving force behind
this is the WEEE Directive. This is a proposal to reduce electrical
and electronic waste that contains lead, one of the fastest growing
waste categories in Europe today. This Directive has been through
a number of drafts and is expected to become a recognised legislation
by 2008. This article looks at the consequences on the PCB manufacture
and possible routes to explore.
The available evidence indicates that measures on the collection,
treatment, recycling and disposal of waste electrical and electronic
equipment (WEEE) as set out in Directive 2002/96/EC of 27 January
2003 of the European Parliament and of the Council on waste electrical
and electronic equipment (6) are necessary to reduce the waste management
problems linked to the heavy metals concerned and the flame retardants
concerned. In spite of those measures, however, significant parts
of WEEE will continue to be found in the current disposal routes.
Even if WEEE were collected separately and submitted to recycling
processes, its content of mercury, cadmium, lead, chromium VI, PBB
and PBDE would be likely to pose risks to health or the environment.
The European parliament is aware that this environmental legislation
could create obstacles that might restrict trade within the European
single market. Whereas the WEEE directive sets minimum levels for
recycling that must be met but may be exceeded, RoHS is very explicit
about which substances should be restricted and the precise levels
that may be tolerated. The directives definition should not vary
across EU member states after translation.
China, as well as other nations not part of the EU, have announced
that they will also adopt the European RoHS directive in 2006.
In the United States, several states are considering similar restrictions,
thus indicative of the growing concern relevant to health and environmental
risks associated with the byproducts of electronic goods.
From 1 July 2006 new electrical and electronic equipment must not
contain lead, mercury, cadmium, hexavalent chromium, polybrominated
biphenyls (PBBs) or polybrominated diphenyl ethers (PBDEs).
These must be replaced by other substances.
Certain applications are exempt from the requirements of the Directive
including mercury in certain types of fluorescent lamps, lead in
the glass of cathode ray tubes, electronic components and fluorescent
tubes, lead in electronic ceramic parts and hexavalent chromium
as an anti-corrosion of the carbon steel cooling system in absorption
refrigerators. The exemptions will be reviewed every four years.
The RoHS Directive requires that manufacturers be able to demonstrate
minimal levels of the following identified substances :
1.
Lead (Pb)
2. Hexavalent chromium (Cr +6)
3. Mercury (Hg)
4. Polybrominated biphenyl (PBB)
5. Cadmium (Cd)
6. Polybrominated diphenyl ether (PBDE)
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