For more than 60 years the electronics industry has relied on tin-lead solder as the primary bond between electronic devices. Its reliability and strength are well-known. Electronics systems built with tin-lead solder have performed in such demanding environments as missile launches, deep space explorations and high performance aircraft missions; and have also withstood shock and vibration onboard ships from high sea states and rapid firing of large bore guns.
But the ever increasing movement to eliminate materials deemed hazardous to the environment has forced the electronics industry to adopt solders free of lead. The introduction of lead-free solder (LFS) into electronics manufacturing presents profound implications regarding the reliability of military electronics systems.
The following discussion addresses the transition from tin-lead solder and its impact on the cost and reliability of existing and future Navy systems.
Concerns for e-waste
The European Union Reduction of Hazardous Substances (RoHS) Directive, which went into effect July 1, 2006, specifies maximum concentration values on new electronics products manufactured with solders containing lead. The RoHS Directive aims to reduce pollution and prevent its damaging effects to the environment; and prevent human health problems due to occupational and post-disposal exposure to these harmful substances.
In addition to lead (Pb), the other restricted substances are: cadmium (Cd), mercury (Hg), hexavalent chromium (Cr (VI)), polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs).
The Waste Electrical and Electronic Equipment (WEEE) Directive is the European Community directive 2002/96/EC on waste electrical and electronic equipment which, together with the RoHS Directive 2002/9595/EC, form the foundation of European law setting collection, recycling and recovery targets for all types of electrical products.
The RoHS directive places the responsibility of compliance on the "producer" of the equipment. Individual EU member states are responsible for enforcement and manufacturers self-declare compliance to the directive.
Restrictions on solders that contained lead were first enacted in the United States and other countries more than 15 years ago for use in metal pipes containing potable water and metal cans that contained food products. Lead is highly toxic and remains stable over time so there are obvious health reasons why solder alloys containing lead are prohibited in these instances.
In an effort to be green, a number of nations have opted to eliminate potentially hazardous materials from electronics, including tin-lead solder. China enacted Article 11, legislation that bans lead and other hazardous substances from electronics in March 2007.
Japan enacted JIS C 095950 (J-Moss or Japan RoHS) in 2006. In the United States, the California legislature passed the Electronic Waste Recycling Act (SB 20/50) in January 2007, which mandates the removal of lead and other hazardous materials from new consumer electronics by 2008.
Who is affected?
Electronics manufacturers that do not comply with the RoHS Directive are not able to sell products in Europe that contain tin-lead solder and may be liable for significant financial penalties for each violation. Other repercussions for non-compliance include lost profits and loss of consumer confidence.
Transition to lead-free solder has been expensive and costs may continue to climb as more manufacturers move to LFS. This is because manufacturers must use alternative materials, retool assembly lines and use different coatings for parts.
There have been negative reports on product quality and reliability resulting from the lead-free restrictions, in addition to the high cost of compliance, especially to small business.
Exemptions to the maximum allowed concentr