Power Electronics

Expanded RoHS May Spell More Work for Manufacturers

If your company has finally gotten a handle on RoHS and feels comfortable in its ability to build systems that meet the directive, get ready for another climb up the learning curve. The European Union (EU) is evaluating the expansion of RoHS to include additional substances (including previously exempt ones) and the elimination of exemptions for certain types of equipment. And even as RoHS grows, there also are additional restrictions being proposed or enacted as a result of other legislation.

So, now that you have the names of the six restricted substances committed to memory, be prepared to learn perhaps another 40 more. That list would include nine substances that the EU RoHS Commission is considering adding to the RoHS directive, plus another 31 additional substances (beyond RoHS) that other European countries and corporate directives are looking to ban.

In the meantime, there are two more substances that will go on the restricted list at the end of this month: One is decabromo diphenyl ether (Deca-BDE; a formerly exempt flame retardant). The other is perfluorooctanesulfonic acid (PFOS; a substance found in photolithographic chemicals), though this is being banned under a separate EU directive (not RoHS).

Some of the proposed additions to RoHS are generating controversy. The IPC, a trade association that represents the interconnect industry, has objected to the process that's being used to expand RoHS. In a recent press release, the IPC took issue with a report issued by the Öko Institute, an organization hired by the EU Commission to study the addition of new substance restrictions to RoHS.

The EU Commission's role is to take recommendations by groups like Öko and draft legislation that can then be voted into law by the EU parliament. The IPC argues that the Öko Institute's recommendations for expanding RoHS are based on “biased and flawed methodologies.”

According to the IPC, “The Institute went beyond the framework initially set by the EU Commission and created new criteria and categories for inclusion within the RoHS directive, proposing now that substances observed in the environment and with concerns about combustion should be prohibited under RoHS. This includes tetrabromobisphenol A (TBBPA), the flame retardant used to protect more than 80% of printed-circuit boards and found to be safe by a comprehensive European Union Risk Assessment.”

With regard to TBBPA, Fern Abrams, the IPC director of environmental policy and government relations, explains why there should not be a rush to ban this substance. “There are other flame retardants, but material substitution is never an easy process and can have significant performance effects,” says Abrams. “Additionally, many of the substitutes have not been as closely studied as TBBPA and may entail unknown risks for the environment.”

I spoke recently with representatives of one power-supply manufacturer, Vicor, to get its take on RoHS. The company explained how RoHS requirements affect so many aspects of power-supply manufacturing. These ranged from obvious (but difficult) tasks such as preventing tin whiskers from forming with lead-free solders to the not-so-obvious burden of convincing exempt customers that the lead-free process used to build their products will not hurt their reliability.

Then there was the difficulty of making sure all of the components and materials used to build power supplies don't contain the banned substances. It's not only about lead, there are the finishes on heatsinks, materials in bobbins, and other materials and processes that had to be changed, evaluated and requalified.

All this, of course, is the tip of a growing compliance iceberg, which also encompasses a European regulation known as REACH — something that could ultimately eclipse RoHS. And while RoHS is by no means a challenge just to companies that make power systems, it's likely to influence the evolution of the power-supply industry in unique and unexpected ways. For instance, maybe the burden of RoHS compliance will create another reason for OEMs to purchase rather than build their power converters.

Whatever the impact, here's hoping that as RoHS continues to expand — both chemically and geographically — all the effort required for compliance will be worthwhile.

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