Life after Lead: Emerging Environmental Mandates Spur Innovations in Connector Development
By Bob Hult, Bishop & Associates Inc.

Industry and lead have had a challenging relationship. First, there was the elimination of lead from paint. Next, the spotlight shone on lead in gasoline. It had been added to most fuels to reduce engine knock, after the impact of this additive on air pollution was measured, unleaded gas become the standard fuel for American cars. Replacing lead in both cases involved change, but acceptable replacements were found, which resulted in a relatively painless transition. Today, the removal of lead and other potentially hazardous materials from electronic products, as mandated by a proliferation of evolving environmental standards, is proving to be more of a challenge.

Lead continues to be a major component of many products, including automotive batteries and ammunition. At end-of-life (measured in years for batteries, less than a second for ammunition), lead is released into the environment. The battery industry has done a good job of recycling; bullets are more problematic. In any case, reducing lead from electronic equipment has become the focus of a series of environmental waste standards, due largely to the pervasiveness of electronic devices used in our daily lives, as well as to their exceptionally short life cycles. Continuous advances in technology create new generations of devices, which turn last month’s must-have products into this month’s trash. The proliferation of electronic devices on a global basis has raised alarms about the amount of hazardous materials that are being released into the environment at accelerating rates.

Electronic assemblies have made extensive use of tin/lead solder as the conductive glue that attaches components to printed circuit boards and wires. The combination of good conductivity, adhesion characteristics, and relatively low processing temperatures, together with years of successful experience, has resulted in a high degree of reliability. Pure matte tin makes a fine plated surface as well as solder joint, and was the logical solution to environmental mandates such as the European Union’s Restrictions on Hazardous Substances (RoHS) legislation. The many implications of making this change to such a widely accepted manufacturing process were less obvious.

Attempts to minimize contamination from obsolete electronic assemblies had been attempted on a spotty basis in the past, but RoHS put teeth into their mandate by prohibiting the sale of non-conforming equipment within any European Union member state. Recognizing the global nature of the electronic market, few equipment manufacturers are willing to walk away from that potential market. The subsequent introduction of additional mandates from emerging markets, such as China, has further driven the imperative to address these environmental standards. The ultimate responsibility for compliance rests with the supplier of the final equipment, but compliance is demonstrated by proving that each component conforms to the standard. Although RoHS addresses six specific materials, lead has been the biggest issue for connectors.

To a large degree, connector manufacturers have adopted the 100 percent tin-plating solution, and in most cases have issued new part numbers to designate the lead-free content. Since pure tin melts at a higher reflow temperature, plastic housing materials were evaluated to determine their resistance to discoloration, warping, and melting. Thin wall sections, or the use of older materials, required the retooling of some products to allow the use of higher temperature rated materials. 

The EU directive allowed the exemption of select industries, such as military and aerospace, due to the lack of data on the long-term reliability effects of lead-free assemblies. Additional temporary exemptions were subsequently allowed to certain medical, telecom, and computing applications. The lack of clear delineations between covered and exempt classes of equipment have been a source of confusion as well as an excuse for ignoring the mandate.

RoHS took effect on July 1, 2006, and over the past 10 months, many issues have been settled, some issues proven insignificant, other remain open, and additional questions have been raised. Collaboration between several industry leaders—including Amphenol, FCI, Molex, and Tyco—has provided an industry response roadmap that has facilitated the transition to lead-free connectors. Tin-lead connectors are now being offered in matte tin equivalents, although some bright tin, as well as immersion tin or silver plating, is used to address specific applications. Gold plating continues to be the plating of choice in high-density connectors, where lower normal forces or high reliability preclude the use of tin.

Concerns about extended lead times and product availability of lead-free connectors did not materialize, as suppliers geared up to meet the user demand; the demand was slower than initially anticipated. It is likely that more than half of connector shipments today are RoHS-compliant, although exact figures vary widely, depending on the market segment. Hardly any military or aerospace equipment manufacturers have adopted lead-free components, while consumer products have converted nearly 100 percent of their production to meet RoHS demands. Distributors initially were concerned that they may be required to maintain dual inventories of both leaded and unleaded components, but close coordination with their customers has insured stocking only the parts their customers require, resulting in modest inventory increases.

Confusion about how to identify leaded and unleaded connectors has largely been solved with the issue of new part numbers for lead-free components. In isolated cases, leaded parts have been obsoleted and only RoHS parts are now available. The transition to lead-free connectors is a continuing process, and is driven by customer demand.

The issue of “temporary” exemptions for specific applications such as medical equipment, as well as server network, and data storage applications using compliant pin technology, has settled down. The ability to maintain these exemptions will be reviewed and amended as more long-term reliability data becomes available.

Certifying component compliance to the connector consumer is being achieved by providing letters of compliance or material declarations on demand. Connector manufacturers are putting compliance data by part number on their websites for easy 24/7 access. Distributors are passing this information through to their customers by adding this data to packing slips. Equipment destined for the global market is being labeled to indicate its status. Although the program is based on a self-declaration disclosure concept, actual enforcement is still a fuzzy area and will be managed by each member EU state.

A major wild card involving the formation of tin whiskers remains an unknown. Research continues to develop an understanding of the mechanisms behind their formation, but this task has proven more formidable than expected. In the short term, connector suppliers are using a variety of solutions, including custom chemistry adjustments to their plating solutions, annealing, alternative non-lead plating, and nickel underplates.

In February of 2006, China entered the environmental debate with a new law entitled, “Administration on the Control of Pollution Caused by Electronic Information Products” (ACPEIP). Although this legislation addresses the same six hazardous materials (lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls, and polybrominated diphenyl ether), the process of managing and documenting them is considerably different.

This program, often referred to as China RoHS, is being implemented in two phases. The first phase requires the labeling of all electronic equipment destined for resale within China, and became effective on March 1, 2007. All products must carry a label that discloses any of the six identified hazardous materials. If an electronic product contains no toxic substances, it can be recycled and carries the green environmentally friendly label.


If any of the listed hazardous materials are present in the product, a different logo must be applied, which indicates the approximate period in years that these materials will not pose a threat to the consumer. At this point there is no scientific process by which a manufacturer can determine how long a particular piece of equipment can be considered to be in this “environment friendly-use period.” China is in the process of publishing a series of guidelines by product type that can be used to help identify an acceptable period.

The second phase will involve material restrictions where toxic substances will be banned. Exactly what equipment will be targeted and when such a ban will be enacted is unknown at this time, although a “catalog” is expected to be published by the end of 2007.

Details on exactly what will be required to satisfy the new Chinese rules are difficult to come by at this point, but it appears that there will be several significant differences between EU RoHS and the new China environmental directive. Unlike RoHS, at this point, it appears that the China rules will offer no exceptions. This may change as the directive evolves, but there has been no indication of an intent to exempt any class of equipment. China may also demand material testing and documentation at the individual component level. Only certified Chinese test facilities may be allowed to perform these compliance tests. How these directives will be actually enforced is also very unclear. Since ACPEIP applies only to products intended for Chinese consumers, connectors or sub-assemblies shipped to China for assembly into products intended for other markets, would not be affected. How China will be able to differentiate the intended end-user of the product is an open question.

Given the market potential of China, and the immense and growing amount of electronic components and end-user product manufacturing that is occurring there, China RoHS will be a major factor in how electronic products are designed and built in the future. Connector manufacturers are watching this developing challenge as well as additional environmental regulations being formulated in Korea, and even within individual U.S. states. Component suppliers have recognized that environmental issues are here to stay, and until the day that global harmonization of standards occurs, will be a continuing challenge.

Bishop & Associates Comments: 

• Global efforts to reduce the amount of potentially harmful substances released into the environment has gained traction over the past few years, and will likely play a significant role in the electronic equipment market for the foreseeable future. Environmental initiatives have focused on both the elimination of certain hazardous materials from electronic equipment, and also a management process to facilitate recycling of materials, rather than allow them to be added to landfills.

• Connector manufacturers have responded with pure matte and bright tin replacements for traditional tin/lead plating, keeping the supply chain fully capable of satisfying user demand. The implementation of RoHS has stimulated the exploration of non-tin alternative plating, which may provide greater flexibility in future connector designs. 

• Some serious questions remain about potential short circuits created by the tendency of pure tin surfaces to generate tin whiskers. This failure mechanism has been recognized as a sleeping giant, and unless resolved, may limit the use of pure tin in many applications.

• Over the past 10 months, the European Union RoHS directives have been widely accepted by both component manufacturers and users. Some questions still remain, but the entire process has settled down, and has not resulted in particularly difficult challenges or added costs.

• The recent introduction of new environmental pollution standards currently evolving in China has added a new layer of uncertainty to the approval process. It appears that equipment that satisfies RoHS mandates will likely be acceptable to the new China ACPEIP standard, but the qualification and documentation process will be significantly different. Equipment manufacturers must currently apply the appropriate label to identify toxic substances and are awaiting further definition on products that must eliminate their use. Major questions involving the certification process, potential product exemptions, and enforcement remain.

• The proliferation of hazardous material standards, as they apply to electronic equipment, exhibit limited commonality from country to country, adding unnecessary ambiguity, confusion, and cost to the conformance process. It is hoped that harmonization of these mandates, similar to what was achieved in radiated emission standards several years ago, may occur sooner rather than later.

• Minimizing the amount of hazardous materials used in electronic equipment, and encouraging the recycling of end-of-life equipment has become a long-term global objective. Production of “green” electronic equipment is becoming a marketing advantage. The pursuit of these goals will influence the design of both components and equipment well into the future. The possibility of total bans on the use of additional materials commonly found in connectors today may require substantial changes in connector design and fabrication processes, including the ability to economically reclaim all materials. Connector manufacturers must continue to closely monitor evolving environmental mandates to anticipate unintended consequences of these efforts and develop responses that minimize the cost impact.

Robert Hult
Director of Product Technology, Bishop & Associates, Inc.
Robert Hult has been in the connector industry for over 36 years. Hult began his career as a sales engineer for Amphenol. He joined AMP in 1972 and served in several management positions through 1996. In 1997, Hult joined Foxconn as group marketing manager for Intel, Chandler, Arizona, U.S.A. Prior to joining Bishop & Associates, Hult was the regional application engineering manager for Tyco Electronics.

Hult graduated in 1968 from Bradley University with a Bachelor of Science degree in electronics technology and a minor in business.