The International Electronics Manufacturing Initiative (iNEMI) High-Reliability RoHS Task Force has published guidelines regarding assembly processes and reliability requirements for RoHS subassembly modules. In a statement, iNEMI notes that with current RoHS exemptions for high-reliability electronics, it is possible for electronic assemblies to contain lead and still be RoHS-compliant. Manufacturers taking the lead exemption will continue to require tin-lead compatible component for their products and may also use subassemblies such as hard disk drives and power modules that may or may not be lead free.
The issue has become a big concern for those in the exempt industries of aerospace, defense, medical equipment and telecommunications, since many of their components are now lead-free. Thus, in many instances leaded components and lead-free components will exist in the same subassembly. “It is very likely that manufacturers will use subassemblies that contain both tin-lead and lead-free components, which causes reliability concerns due to the differences in processing temperatures and materials,” says Thilo Sack, principle engineer, corporate technology at Celestica Inc., and co-chair of the iNEMI High-Reliability Task Force.
The guidelines are intended to help manufacturers producing high-reliability products to work through these issues effectively.