If you think going lead-free is largely a manufacturing problem, think again. A little less lead may cause big problems for the supply chain.

To date, the electronics industry has endeavored to develop lead-free pastes and solders in anticipation of the European Union's ban on lead, set to go into effect in July 2006. But the industry has paid less attention to the problems of identifying, storing and tracking the components that are phasing out lead as well.

Knowing what contains lead and what doesn't is going to become crucial as the industry transitions from leaded to lead-free products, says Ken Stanvick, a partner in the high-tech consultancy Design Chain Associates. Lead-free components require different storage, handling and soldering processes than those with lead. But so far, the industry does not have a consistent method for identifying which products contain lead and which don't.

Problems arise because lead-free components are soldered to printed circuit boards at higher temperatures than leaded ones. They aren't swappable—components can crack under the wrong processing conditions. Differences are not visible to the naked eye. Some manufacturers put a "lead-free" label on their bulk packaging, others on the component themselves. And in an industry that already has problems tracking its inventory, "This will create a logistical nightmare of what I ordered versus what I got," says Stanvick.

Lead-free products also have different moisture sensitivity ratings, he says. Parts that have not required dry packing in the past will in the future. This creates particular problems for distributors, which often break down large packages of components into smaller lots for their customers. If they come dry-packed, they'll have to be repackaged, which likely will add time and cost to the process. Shelf life may also be compromised: Components manufactured with pure tin plating should not be stored longer than one week at temperatures below 13 degrees centigrade, because the tin begins to degrade. This causes electrical continuity problems and problems with the tin's solderability.

Initially, lead-free components may be in short supply. Component makers are limiting capital equipment investments during the downturn, and component inventories are way down. Any sudden surge in demand for lead-free components may create a shortage. And suppliers may use this transition period to discontinue leaded product lines that are popular but not necessarily profitable.

Finally, any company specializing in after-market repair will face a challenge if lead-free alloys are not identified. Although most manufacturers use a mixture of tin, copper and silver, the levels of the elements within each alloy differ from product to product. Mixing two alloys on a single board actually creates a third alloy that may have different temperature tolerances than the first two.

Lest consultants be accused of warning about problems they themselves are poised to solve, Stanvick points to several associations tackling these problems (see box). His advice: Make sure you understand your suppliers' technology road map. Track which products they are taking lead-free. Read all you can on the topic, and don't rely on the hope that problems will be solved for you. The industry is definitely going lead-free, but it's going to take a concerted effort to get there.