March 9, 2009

Unintended Consequences of RoHS: What Can They Mean to You?

In the 1980s I worked for a company that made diodes. It was a small company and our technology was not the most modern, but we had intellectual property that allowed us to make some excellent products. Around that time, the State of California began to recognize that lead, when handled improperly, was a serious health hazard. Legislators contemplated an embargo on producing any goods containing lead within the state's borders and, as I recall it, they didn't want products containing lead coming into the state from outside.

This proposal caused some of us to chuckle a bit. Remember that those were still the early days of the microprocessor/PC revolution. California was at the epicenter of that activity. Essentially every electronic product being made at the time contained lead in some quantity. Following through on the state's proposed directive would have killed the California gold rush and probably the entire electronics industry--clearly an unintended consequence.

Here are some concerns we've helped our customers explore that could have resulted in unintended consequences:

Does it pay to re-engineer legacy products to remove lead solder and/or components containing lead?

Strictly considering the economics--without addressing technical matters--re-engineering has the usual cost implications.

First, the project costs. How many engineering man-hours are necessary? Clearly this is a function of product complexity and should be less than a clean sheet of paper design. However, it's easy to underestimate the difficulty of finding direct replacements for components that may have been originally designed years ago.

Will a re-design trigger a comprehensive testing regimen and possible regulatory evaluations? Will what was once an exercise in part substitution become a total re-design If so, what is the anticipated remaining product life and will the incremental costs of the project be amortized?

Second, what about the ongoing availability of components and their costs? We've seen this go both ways. Sometimes, there is an ocean of parts out in the marketplace and at their costs could be less than the originals. Conversely, some RoHS parts, especially through-hole or semiconductor parts, become obsolete quickly. They can be exceptionally expensive, perhaps to the point of ruining the overall product economics. Obviously, it is essential to learn about this latter case early in the process. Otherwise, ugly surprises can happen.

So does it pay? Maybe.

What about designing all new products exclusively RoHS?

De-facto, there is much movement toward RoHS because component suppliers prefer to have only one offering per product rating. And, most people would agree that less lead is better all around. So, anything new is generally biased in favor of RoHS. Maybe in 50 years, everything will be.

But for now, we can help you ask the pertinent questions: Are RoHS products suitable for the operating environment of your systems? What about fatigue? Embrittlement? Transportation or military applications? Low temperatures?

We've learned that one size does not fit all--RoHS products are not always ideally suited to certain working environments. For example, in transportation or low temperature applications, RoHS solder, as opposed or solder with lead, makes joints that are too brittle and don't survive harsh conditions like thermal or mechanical stress. Another problem is that lead-free solder can sometimes generate small plumes of material--tin whiskers--that can then cause electrical short circuits across very small SMT components or circuit board traces.

So what? Let's make careful evaluations on a case-by-case basis to avoid bigger problems. As with many things in this business, complying with RoHS requires good judgment. It's easy to throw money at a problem and hope it goes away, but a thoughtful analysis can save time, money and lots of grief. See you next month.

--Jeff Cosman


Back to main QC page