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Bringing new and innovative products to market can present numerous challenges to companies and their product development teams. Perhaps the most daunting of these challenges is providing assurances that a newly designed product will function as intended and not fail or malfunction under all anticipated operating scenarios.
Highly accelerated life testing (HALT) and highly accelerated stress screening (HASS) can be effective methods of exposing potential failure modes and design flaws in a product. When conducted early in the design process HALT testing can accelerate the product development timeline, reduce overall development costs, and minimize the risks associated with substandard products by determining the limitation of design. In post-production phase, HASS testing evaluates production reliability.
Omar Runcie is Nemko’s experienced testing engineer responsible for HALT/HASS testing at our Oslo, Norway testing facility. With nearly 20 years of experience in the evaluation and testing of advanced technologies in a variety of industries, Omar has a first-hand understanding of the potential problems in new product designs, and how HALT/HASS testing can help mitigate them.
In a recent interview, Omar discussed the specifics of HALT/HASS testing and its importance in the development cycle of advanced electrical and electronic products.
What is HALT/HASS testing, and what it is designed to achieve?
HALT/HASS testing is a “test-to-fail” technique in which a product is exposed to multiple cycles of extreme variations in temperature, repetitive shock and vibration, or both.
During HALT/HASS testing, a product can be exposed to temperatures that change in a matter of minutes from as low as -100 degrees Celsius to as high as 200 C, while also undergoing random vibrations of up to 75Grms (root-mean-square-acceleration). Although a manufacturer or developer may provide temperature and vibration specifications for a given product or device, HALT/HASS testing is usually conducted until the product fails.
The combination of testing conducted under the HALT/HASS methodology allows us to determine weaknesses or potential failure modes of a product much more quickly than traditional testing approaches. Doing so helps to lower the risk of warranty issues or product recalls with products on the market, which can represent a significant expense for companies and threaten their brand reputation with customers.
HALT/HASS testing has been around for almost 30 years. How have HALT/HASS testing methodologies changed over time?
The principles that define HALT/HASS testing haven’t changed much since the testing methodology was used in the early 1990s. What has changed is
the level of technical sophistication found in today’s testing chambers and equipment. One example is advancements in the actuators used to manage air flow which controls vibration. This and other improvements have helped make the results achieved with HALT/HASS far more repeatable and reliable, which is especially important when testing a large number of samples of the same product or component.
Are there specific types of products that are best suited for HALT/HASS testing?
Some of the earliest applications of HALT/HASS testing were found in assessing the reliability of electrical and electronic equipment used in extreme climates such as the Arctic region or in the deserts of the northern most portion of the African continent. Over time, however, its use has expanded to other applications where harsh environmental conditions can be expected, such as aerospace and oil, gas and petroleum technologies. The automotive industry is also a major user of HALT/HASS testing, where its application can help assess the reliability of critical safety systems.
How long does a HALT/HASS testing cycle take to complete?
Before the actual testing process begins, we need to have a thorough understanding of just how the product will be used in the real world. Of course, the product manufacturer will provide us with basic information on that front, but we then need to determine a test regime that is most likely to evaluate all of the potential use conditions to which the product is likely to be subjected. Then, we can develop a comprehensive HALT/HASS testing plan that will assess the performance of the product under each of those conditions.
Another factor is the size of the product or component and the number of samples to be tested. Since testing chambers have defined capacity limits, multiple samples of a smartphone, for example, can be tested in a single testing cycle, while it might require multiple testing cycles to evaluate the requisite number of samples of a larger product.
On average, the entire testing process can typically be completed within a few days up to a few weeks depending on the product But certain results can quickly be found within a few hours.
What are the some of the advantages of HALT/HASS testing over more traditional testing methods? Are there any drawbacks or downsides?
As I mentioned previously, HALT/HASS testing generally requires stressing a product or component beyond the design specifications until it fails. For that reason, it enables us to quickly identify potential weakness in the product design, or aspects of the product where failure is most likely to occur. This enables developers to address these failure points early in the product design process, thereby helping to avoid lengthy delays required to address design flaws later on.
The one potential drawback is the cost of supplying product or component samples for testing. Since HALT/HASS testing is intended by design to achieve product failure, product samples are generally not usable after testing and must be repaired or discarded.
Can you give us 1 or 2 real-world examples of situations in which HALT/HASS testing has made a positive difference to a client?
Sure! In one recent case, a client unexpectedly learned that a capacitor component critical to their product was no longer available. On behalf of the client, we used HALT/HASS testing to evaluate five different alternative capacitors from multiple suppliers and compared the testing results against those of the original capacitor. The testing enabled the client to quickly identify a replacement supplier for an essential part, thereby preventing a costly interruption in their production.
In a second instance, we found solder joint failures in several large components of a client company’s printed circuit board (PCB). Using HALT/HASS testing, we traced the solder failures to an insufficient amount of solder used during the PCB assembly process. By simply modifying their production process to increase the amount of solder, the client was able to satisfactorily address the source of the PCB failure.
Why should companies consider undertaking HALT/HASS testing with Nemko?
At Nemko, we take a consultative approach to HALT/HASS testing. We work directly with our client companies to understand their specific testing requirements and to develop a testing plan that addresses all of their concerns. And with decades of experience at hand, we are able to advise clients on the significance of our testing results and help them to develop cost-effective solutions that get their product development process back on track quickly. Finally, our state-of-the-art HALT/HASS testing capabilities are second to none, allowing us to offer the most reliable testing solutions available.
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