RoHS war stories
per will not delve into the advantages and ery was purely accidental or whether the aluminum for machining purposes
disadvantages of one over the other but Dutch authorities were tipped off. • Lead in glass frit
simply assume that one of the scenarios is About a year ago, Swedish authorities • Lead in flip chip attachments
applicable to each company attempting to were considering renting two handheld • Lead in solder of network infra-
attain and maintain RoHS compliance. XRF spectrometers for RoHS testing
2
. This structure products (often referred
would certainly lead one to believe that any to as being “RoHS 5 of 6 compli-
rohs substances and thresholds instance of non-compliance is more likely ant”)
Of the six elements/compounds being to be exposed because a competitor or
Cadmium poses yet another major
tested for (Table 1), lead (Pb) is the most NGO has the ability to expose these infrac-
problem for RoHS testing. With a pass/
ubiquitous. It is therefore no surprise that tions to enforcement authorities. Once a
fail limit of 100 ppm (per homogeneous,
it is the material mostly likely to be tested
mechanically sepa-
for and the one most
rable material), it is
likely to be exposed
debatable whether
during an audit or
“This part is lead-free, there is no lead in the part, all XRF units
inspection. It is for
this reason that most
all the lead is in the balls under the part.”
(especially portable
XRF) that are being
of the stories below
used can accurately
are based on this
detect cadmium at
particular element.
this level. Cadmium
Some of the stories would be funny if this claim of non-compliance has been made,
testing with XRF is further complicated
was not such a serious issue and liability the enforcement bodies can then proceed
due to false positives. Unlike lead, the false
for so many manufacturers and Sony to use their analytical instruments to verify
positives are not instances of exempted cad-
certainly knows this, as most people in this them against the possible offender. The
mium presence but the result of spectral
industry are very aware. practice of manufacturers conducting
overlap. If there is any significant presence
A few years back Sony sent pallet loads independent analysis on their competitor’s
of tin or antimony in a sample, spectral
of an early Play Station™ module into products and reporting any infractions to
overlap can artificially raise the cadmium
the Netherlands for the Christmas rush. EU enforcement authorities is becoming
detected by the spectrometer.
The following is the likely enforcement commonplace and is even being encour-
Chromium is often present in alloys as
scenario: aged in some EU member states.
a base metal, as a component of an alloy
A Dutch customs inspector cut open a Aside from being ever-present, lead
(1-57% in stainless steel), for decorative
shrink-wrapped pallet with their box knife, also has the largest number of application
purposes or as an alloy finish. The latter
took a unit back to their inspection area, exemptions. These are understandable, as
causes issues because zinc chromate and
opened it, used a screw driver to remove lead has had multiple areas of use and has
anti-rust finishes are also used in the
the cover, and then used wire cutters to re- been a staple in the electronics industry for
same types of situations. Even if Cr(VI)
move one particular plastic sheathed wire, decades, and even longer in other indus-
can be found and measured, the question
which was then sent to a lab for testing as tries. Finding safe, reliable replacements (if
becomes “what is the actual weight of the
per their country-specific legislation that ever) will take some time. However, these
homogeneous material that contained the
pre-dated RoHS. There was a provision exemptions result in a very big problem—
Cr(VI) and the weight of the Cr(VI) itself?”
for a cadmium (Cd) ban in that legislation false positives.
For this reason, enforcement scenarios
and the lab testing found high levels of the Of the few dozen listed RoHS exemp-
typically rely on wet-chemical spot testing
substance in the plastic. The cadmium was tions
3
, 21 are for lead. Of these, the most
for detection, and most failures are deter-
presumably there as either a colorant or as commonly used by the electronic industry
mined by conclusively identifying whether
part of a plastic stabilizer. Regardless of its in general are:
or not the substance was intentionally
purpose, the discovery was made public. As
• Lead-containing ceramic (e.g. lead added or not.
a result, Sony was fined, and the delay cost
titanate) PBB and PBDE have been and will
Sony the Christmas market. At some point,
• Lead present in the form of high continue to be the most difficult aspect of
on their website, Sony admitted that this
lead solder (>85% Pb), usually for RoHS to control and enforce against. Very
single event can be pinpointed as having
die attach few labs have gas chromatography/mass
cost them the equivalent of $100,000,000
• Lead added to copper, steel and spectrometers (GC/MS), even fewer are ac-
(US). One can wonder whether the discov-
credited with a governing body, and fewer
still can competently test for the two fami-
Substance Threshold
lies of banned brominated fire retardants.
Lead (Pb) > 1000 ppm
Companies requiring this testing must be
very careful in picking their suppliers for
Mercury (Hg) > 1000 ppm
this service.
Hexavalent Chromium Cr(VI) > 1000 ppm
Polybrominated Biphenyls (PBB) > 1000 ppm
component specifications,
certificates of compliance (cocs)
Polybrominated Diphenyl Ethers (PBDE) > 1000 ppm and lab reports
Cadmium (Cd) > 100 ppm
1. A component specification sheet lists
on the first page a component as RoHS
Table 1. RoHS substances and thresholds being tested for. compliant, showing a simple part
www.globalsmt.net Global SMT & Packaging – June 2009 – 11
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