Circuits Assembly Online Magazine - NEMI Issues Recommendations for Lead-Free Part Identification

The National Electronics Manufacturing Initiative's (NEMI, Herndon, VA) Component and Board Marking Project has made recommendations for the identification of electronic components and board assemblies that have been modified for use in lead-free assembly processes. The team has also identified standard vocabulary terms to create a common terminology related to lead-free processing.

The conversion to lead-free products poses challenges as companies deal with the logistics of handling leaded and lead-free products for manufacturing, rework and field returns. Lead-free processing requires higher temperatures and tighter process windows, which necessitates segregation of leaded and lead-free parts. For the immediate future, manufacturing facilities will be running both leaded and lead-free processes, and rework facilities will be running both processes for an even longer time. Manufacturers must identify lead-free parts and keep them segregated to ensure legislative compliance.

"To prevent manufacturing errors and defects, the assembly shop floor and recyclers need to identify the materials contained in the solders used in the bill of materials (BOM) and the board assembly process," said Vivek Gupta, program manager, Lead-Halogen Free Development for Intel Corp. and chair of the NEMI Component and Board Marking Project.

The NEMI team provided input and supported the development of JEDEC standard JESD97: Marking, Symbols and Labels for Identification of Lead-Free Assemblies, Components and Devices, which was released in May of this year. NEMI considers the identification model in this standard comprehensive enough to meet the needs of manufacturing.

In addition to the guidelines in the JEDEC standard, NEMI is recommending the use of unique part numbers for lead-free materials, components and boards to distinguish them from tin-lead versions.

"Manufacturers' part numbers are critical data elements used to keep track of bill of materials and products during manufacturing, inventory and order fulfillment," said Alan Ater, supply chain manager for Sanmina-SCI Corp. and co-chair of the Component and Board Marking Project. "Unique part numbers for lead-free BOMs will help minimize the chances of mixing tin-lead and lead-free parts."

NEMI has also developed three standard vocabulary terms in an effort to establish a common language for communication of lead-free transition status. The terms defined by NEMI are: Lead-free second level interconnect, Lead free and RoHS compliant. However, the project team decided not to develop a guideline for identification of RoHS compliance or the various phases of lead-free implementation.

The definitions have already been included in the RosettaNet dictionary of terms RNTD version 4.0 and have been proposed to IPC and JEDEC for inclusion in their dictionary of terms.

The recommendations are available at: http://www.nemi.org/projects/ese/Component_BoardMarking.html.