Restriction on Hazardous Substances (RoHS) is considered “…the most far reaching piece of legislation ever to impact the electronics industry.” This is according to the Canadian firm Celestica Electronics, quoting directly from Janes Defense Weekly, 8-24-2005.
The deleterious effects on electronics reliability caused by the removal of lead (Pb) from the solders and component/piece-part surface finishes used for electronics manufacturing for the last 60+ years, called “Pb-free electronics” (and a direct result of RoHS) are now in full effect. As an example, the EMPF has encountered numerous occasions where customers have had been caught unaware of the how changes in the commercial off the shelf (COTS) product stream affected the availability of certain materials, resulting in the inadvertent utilization of incorrect manufacturing process conditions (Figure 6-1). The consequences to the product integrity due to mismatched tin-lead (SnPb) and Pb-free material sets were not known at the time, since may of the potential issues can remain latent until the systems have been implemented in field conditions.
Since the RoHS banning of Pb in electronics (and years before that, anticipating the change), many defense industry prime contractors, such as Boeing, Raytheon, Lockheed Martin, Northrop Grumman, ITT Avionics, Honeywell, and Rockwell Collins, have been searching for some way to be able to guarantee to their Government customers some specific level of reliability in the electronic gear that they are selling every day. But prediction (and predictability) of the long-term, harsh environment reliability of Pb-free electronics remains elusive. Reliability predictions for Pb-free electronics are steeped in the complex metallurgy, physics, and materials science of the ternary (and sometimes quaternary) “replacement” Pb-free solder alloys and pure tin surface finishes, and the complex organic circuit board composite materials, offered by the commercial industry. While these new Pb-free materials fill commercial and much less stringent consumer requirements, those of aerospace and defense (A&D) often exceed them by a large margin.
Adding to this knowledge gap is the fact that many commercial electronics applications, such as games, MP3 players, cellular telephones and personal computers, have been able to switch to the Pb-free electronics mandated by the RoHS law with hardly any perceptible reliability consequences due to their short life cycles and benign environment (compared to A&D environments) products. These commercial industry “remedies, solutions, and mitigators” become most misleading when considering the A&D harsh environment, long lifetime, and often life-critical electronics requirements. All of this causes an erroneous perception within Government that industry is “dealing with the problems” of Pb-free electronics. Increased use of COTS electronics in A&D systems compounds the problem, as the COTS electronic hardware is generally RoHS compliant, with generous quantities of pure tin plating and commercially-oriented Pb-free solder alloys.
The EMPF has helped the commercial Pb-free manufacturing sector by offering a two-day course, titled “Lead Free Manufacturing” consisting of two half-days of lecture in the subject of Pb-free electronics and two half-days of hands-on manual, wave and surface mount Pb-free assembly soldering, rework, and repair of actual Pb-free electronic assemblies in the fully equipped EMPF Demonstration Factory. The EMPF has been proactively involved in instructing a variety of companies in Pb-free manufacturing to suit their commercial applications. Conversely, forward-looking contracting organizations and individuals of the A&D community have recognized the need for concentrated training in regards to the risks of Pb-free electronics in A&D electronic hardware application. In order to mitigate the effects of Pb-free materials from entering into the product stream, contingency plans (Figure 6-2) and systems must be developed to meet the upcoming Department of Defense (DoD) acquisition policy to all suppliers of military hardware.
In a response to the industry’s need for a Lead Free Control Plan (LFCP), the EMPF is currently developing a course that will help meet the transition required with the adoption of the DoD policy concerning the use of Pb-free electronics within any military acquisition program. The LFCP will be geared to incorporate within the overall existing manufacturing system which integrates a comprehensive approach toward Pb-free mitigation. The EMPF course is designed to include training in transitioning the LFCP into:
- Quality Systems
- Design Technology
- Material Controls
- Production Technology
- Process Controls and
- Employee Training.
Additionally, the EMPF offers an array of engineering expertise to help expedite the LFCP process within your manufacturing work site through consultation and a thorough readiness assessment of your production facility to meet the plan requirements.
All of the standard courses on the EMPF roster (see the complete 2010 schedule at the close of this newsletter) are administered in Philadelphia, but can be taught at virtually any suitable location for in-house training if desired. Custom Pb-free electronics modules have been incorporated into several EMPF training courses on conformal coating and electronics manufacturing and can be adapted on a customer-by-customer basis as well. Contact the Registrar for information on any of the courses at 610.362.1295 or via email at registrar@empf.org.
Further questions regarding RoHS compliance, DoD policy concerning the use of Pb-free electronics, LFCPs and subsequent training can be directed to Fred Verdi via telephone at 610.362.1200 extension 201 or through email at fverdi@aciusa.org.
This article has been co-authored by Fred Verdi and Carmine Meola.
