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The program manager's guide to Pb-free: a review of the new GEIA handbook for managing the Pb-free transition.

While the RoHS Directive includes exemptions for the defense and perhaps aerospace markets, the greatest challenge to these sectors comes from their suppliers. Many major component manufacturers and subsystem producers are already in the process of using Pb-free materials. Pb-free technology has proliferated across all electronics products and is currently impacting product manufacturing, reliability, rework and the sustainment of programs. Thus, the question looms: How does the introduction of Pb-free materials affect aerospace and military programs requiring high-performance and high-reliability electronics?

Lead is a key ingredient of electronics solders and component terminations. Its elimination is causing a significant shift to the way electronics are manufactured, repaired and used. This shift has caused major concerns in the program management and acquisition community, particularly in the DoD and aerospace sectors. There has been an outstanding need for information for program managers (PM) for guidelines or criteria on how to address the onslaught of Pb-free technology.

To address these technical issues, a number of industry groups and technical bodies are coming up with standards and handbooks. The GEIA-LEAP Program Managers Handbook is one of four publications planned by the AIA-LEAP on the subject. Pb-free materials and processes are relatively immature and poorly understood. As such, an aerospace/DoD-wide approach to the transition is deemed highly valuable. To that end, the Aerospace Industries Association (AIA), the Avionics Maintenance Conference and Government Electronics and Information Technology Association (GEIA) have formed a joint working group, "LEAP" (Lead-Free in Aerospace Project), with the express purpose of generating a series of international standards covering handling and use of Pb-free solders and components in military and aerospace applications. These documents are specifically targeted at Performance Standards (GEIA-STD-0005-1), Technical Guidelines (GEIA-HB-0005-2), Risk Mitigation for Tin Whiskers (GEIA-STD-0005-2) and Program Management and Systems Engineering Guidelines (GEIA-HB-0005-1). Figure 1 shows the conceptual organization and scope of these documents.

The handbook covers discussion of major topics and issues associated with introduction of Pb-free technology in new and existing programs. This document provides a high-level framework for bringing together Pb-free issues and allows a methodical approach to evaluating the impact. Major topics covered are:

General discussion of PM concerns. Technical concerns reviewed are: reliability, configuration control, risk management, effects of tin whiskers and repair/rework and maintenance. Program concerns reviewed are: cost, parts obsolescence, quality, contractual language and existing program constraints. Also described: a matrix of reliability concerns at the program level.

Requirement definition. The handbook recommends re-evaluating program requirements to consider customer requirements, RoHS rules, prime contractor requirements and elements required for contractual authorization.

Environmental consideration. The PM should evaluate the use environment, storage and transport conditions and the definition of "critical" to assess the performance of Pb-free solders under these conditions and to understand possible differences in solder behavior.

Decision criteria. Several decision steps and criteria are provided, including checklists to assess supplier compliance to GEIA performance standards and obtaining and evaluating Pb-free performance plans from suppliers.

[FIGURE 1 OMITTED]

Requalification test/plan. A recommendation to evaluate product to determine if the transitioning product should be requalified, delta qualified or accepted by similarity.

Rework/repair and maintenance. The document recommends obtaining procedures from the supplier, and maintenance and training documents.

Risk management. The document recommends the PM identify, analyze and mitigate program-level risks.

Cost. The PM should conduct program cost-impact analyses, including risk management, delta qualification impact, rework/repair/maintenance impact, warranties and schedule impact.

Currently no policy guidance is available to program managers. This handbook presents a good starting point for PMs and provides a schematic framework to bring together all program-related high-level aspects of Pb-free. It highlights technical and program areas for review and generates a discussion of program lifecycle phases among the program team members. Checklists provided are useful and offer a detailed view of how current and future programs will be affected.

The document provides a schematic approach to assess the impact of Pb-free technology and topics are described in an advisory rather than rulebook format. Note that the tasks implied are high-level and do not provide sufficient details at the practice level. Indeed, Pb-free is in its infancy as a large-scale technology and the technical information required to implement many programming aspects is not complete. As a result, a specific action plan, regarding for example, the reliability of a circuit board or risk matrix parameters, is not yet available. In addition, each program has a different scope and diverse program needs, which need to be taken into account to further solidify actions at the practice level. During the Pb-free transition, the handbook should be treated as a living document that is expected to be updated as substantiated information and data become available.

The American Competitiveness Institute (aciusa.org) is a scientific research corporation dedicated to the advancement of electronics manufacturing processes and materials for the Department of Defense and industry. This column appears monthly.
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Title Annotation:Soldering Tips
Publication:Circuits Assembly
Date:Mar 1, 2006
Words:807
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