Last month, a U.S. House of Representatives committee asked the Missile Defense Agency to consider the use of Highly Accelerated Life Testing and Highly Accelerated Stress Screening (HALT/HASS) for identifying possible reliability issues in critical ballistic missile defense (BMD) systems and components.
The committee also believes HALT testing can help ferret out unreliable counterfeit parts that enter into the missile defense supply chain.
From the report:
“Effective utilization of modern methods and equipment for highly accelerated life testing and highly accelerated stress screening (HALT/HASS) during early design stages has been demonstrated to yield significant improvements in reliability and more effective product designs, as well as cost savings. Through modern HALT/HASS testing, key components and subcomponents are subjected to overstresses, revealing latent design flaws (including those based on the use of faulty or counterfeit parts) that can go undetected with legacy testing approaches.”
The House committee asks the Director of the Missile Defense Agency to conduct an assessment of the value, feasibility, and cost of greater utilization of modern HALT /HASS testing equipment and processes to:
- Shorten design and development timelines
- Reduce system and component testing and lifecycle costs
- Enhance reliability of critical missile defense systems and components
- Help address the growing problem of detecting and preventing the introduction of counterfeit parts
The Missile Defense Agency Director is asked to provide his recommendations regarding use of HALT/HASS by January 15, 2014.
Learn why HALT tests are superior to traditional reliability tests in a free HALT webinar next week.
Ask to tour MET’s HALT testing setup in one of our environmental simulation labs.
Highly Accelerated Life Test (HALT) chamber manufacturer Qualmark recently completed an interesting study, where it compared test data from 47 HALT tests in 1995-96 to data from 47 tests in 2007-08. The purpose of the study was to gauge the effect of the transition from the use of through hole printed circuit boards (PCBs) that were predominately used in the 1990s to the surface mount PCBs predominantly used today.
The order of the applied stresses was the same in all tests:
- Cold step
- Hot step
- Rapid thermal
- Combined vibration and rapid thermal
The study found that, in general, the surface mount PCBs fared much better from a vibration standpoint. There was a 58% reduction in the fraction of vibration failures versus the earlier data.
On the other hand, the fraction of failures due to rapid thermal stresses more than doubled for surface mount PCBs, as compared to older through hole versions.
Additionally, the earlier data showed that 20% of the failures discovered in HALT required the extreme stresses of the combined environment. The figure increased to 32% for the latter test group. This would seem to indicate that today’s electronics are more robust, although in the earlier group, there were 5.0 failures per test, as compared to 6.25 failures in the more recent group.
Although there were some differences between the test groups (e.g. the types of products tested) it seems clear that HALT testing is still relevant and necessary for today’s surface mount electronics, especially in the combined vibration and rapid thermal environment.
For more on HALT testing, register for MET Laboratories’ January 11, 2011 webinar: “HALT Testing Effectively”