Investigations of Toyota vehicles have revealed tin whiskers in a critical component of their vehicle engine control system. At the 5^th International Symposium on Tin Whiskers, Henning Leidecker and his team at NASA's Goddard Space Flight Center, who are recognized experts on electronic device failure and tin whiskers, presented their studies of tin whiskers on Toyota electronics. They determined that the risk of failure due to tin whisker shorting in affected Toyota vehicles can be on the order of 50 to 150 per million. This figure agrees with the number reported in a recently published scientific journal article written by CALCE researchers Bhanu Sood, Michael Osterman, and Michael Pecht. In this study, the probability of a tin whisker induced electrical short was estimated to be 140 per 1 million, based on whisker growth statistics.

Tin whiskers are known to grow from tin-finished surfaces and have been associated with costly failures of electronic systems. Linking tin whiskers to electronic product failure is often extremely difficult. Tin whiskers that bridge across terminations can create electrically resistive pathways. And since whiskers shift under an electrostatic field and can melt when the electrical current is drawn, they may cause intermittent electrical failures.

Figure 1 Tin whiskers on the edge of an acceleration position sensor board connection terminal in a 2002 Toyota Camry.

Considering the number of vehicles on the road, the presence of tin whiskers in engine control components presents a significant safety hazard. For this reason, best practices for electronics design stipulate that tin not be used as a plating material. It is very questionable why the National Highway Traffic Safety Administration with its stated mission to "save lives, prevent injuries and reduce economic costs due to road traffic crashes, through education, research, safety standards, and enforcement activity" has not come out with a requirement that no electronics associated with control of automobiles use pure tin as a material component, since the potential for tin whiskers presents an unreasonable and unnecessary risk.

To learn more about this study, please click here. For more information related to tin whiskers, contact Michael Osterman at osterman@calce.umd.edu. If you found this article interesting, check out more on CALCE's tin whisker research, here.

CALCE has published a paper on its research into Diminishing Manufacturing Sources and Materials Shortages (DMSMS) obsolescence, which is defined as the loss of the ability to procure a technology or part from its original manufacturer. The ability to forecast when technologies and specific parts will become unavailable (non-procurable) is a key enabler for pro-active DMSMS management and strategic life cycle planning for long field life systems. CALCE has proposed a methodology for predicting the obsolescence dates for electronic parts that do not have clear evolutionary parametric drivers. The method is based on the calculation of procurement lifetime using databases of previous obsolescence events and parts that have not gone obsolete. The methodology has been demonstrated on a variety of electronic parts and it has been used in trending of specific part attributes. Click here to read more or contact Professor Peter Sandborn at sandborn@calce.umd.edu.

If you found this article interesting, check out more on CALCE's research on obsolescence management, here. Also, check out CALCE's professional development courses on prognostics and health management.

Bhanu Sood

CALCE Failure Analysis Laboratory Director Bhanu Sood will lead a half-day professional development course (PDC) at IMAPS 2011 where he will provide an overview of the electronic parts supply chain, potential drivers for counterfeit parts, and the sources and the extent of the counterfeit electronics problem. A large section of the course will be devoted to the tools and techniques that can be used to positively identify suspected counterfeit parts. The PDC will be held from 1-5 p.m. on Sunday, October 9, 2011, at IMAPS 2011 in Long Beach, CA. For more information please click here or contact the course instructor, Bhanu Sood, at bpsood@calce.umd.edu or by phone at 301-405-3498.

Professor Michael Ohadi

Professor Michael Ohadi will lead a one-day short course on next-generation thermal management of electronics, with a focus on energy efficiency, on October 24, 2011 at the University of Maryland. This short course will review the latest progress in thermal management and thermal management of electronics in particular. Energy efficiency, methods that may be most suitable to meet future needs of diverse applications, thermal management of 3-D electronics, and energy management in data centers will also be discussed. This cost of this short course is $250 USD for CALCE and CEEE Members, and $500 USD for non-Members. For more information, click here or contact Prof. Ohadi at ohadi@umd.edu.

The CALCE Electronic Products and Systems Consortium (EPSC) will hold its Fall Technical Review and Project Planning Meetings from October 25-26, 2011, at the University of Maryland's College Park campus. CALCE investigators will provide year-end reports on FY11 projects and plan the schedule of projects for FY12. EPSC Projects presented at the meeting, will include: electrical aspects of tin whisker failures, degradation analysis of lithium ion batteries, high temperature solder system for improved reliability, multi-axial vibration test methods, and much more. In addition to the EPSC projects, the Prognostic and Health Management Consortium projects will be presented in a special section. This event is free for CALCE EPSC and PHMC members. Non-EPSC organizations interested in attending the technical review should contact Dr. Michael Osterman at osterman@calce.umd.edu.

For more information on CALCE EPSC, please visit: http://www.calce.umd.edu/consortium.html.

CALCE and Buehler will hold a three-day short course on failure analysis of electronics from Nov. 1-3, 2011 at the Technical University of Denmark in Lyngby, Denmark. This intensive short course will offer lectures, demonstrations, and hands-on laboratory training in failure analysis methodology. For more information, click here or contact Bhanu Sood, at +1 (301) 405-3498 or by email at bpsood@calce.umd.edu, or Dr. Michael Azarian at mazarian@calce.umd.edu.

CALCE presented its research on Multi-Degree of Freedom (MDOF) Vibration Testing on September 20, 2011. MDOF testing is at the forefront of vibration testing and is already used in a wide variety of industries including defense, aerospace, and automotive. Today, MIL STD 810 includes guidelines for MDOF testing. Attendees of the seminar learned about the results from the latest research in MDOF testing and received up-to-date information on the systems used to conduct these tests. For more information, please click here or contact Prof. Dasgupta at dasgupta@calce.umd.edu.

CALCE saw a strong turnout at the Fifth International Symposium on Tin Whiskers, held from September 14-15, 2011 at the University of Maryland. The two-day symposium covered theories of tin whisker growth, risk evaluation methods, and risk mitigation strategies through presentations by representatives from Nippon Avionics, Robert Bosch, Sandia National Labs, NASA, NIST and many more. More than 70 attendees from over 30 organizations learned about the current state of knowledge and received guidance in developing effective qualification and mitigation procedures for their products. For more information, please click here or contact Dr. Michael Osterman at osterman@calce.umd.edu.