Highly Accelerated Life Test: EMIRS 50 Performs Up to the Limit of the HALT Chamber Without Any Weak Points
Axetris, Leister Corporate, Infrared Sources
To ensure the durability of EMIRS 50 infrared sources, Axetris subjects device components to various stress tests. One quality test that has made a name for itself, particularly in the USA, is the HALT – Highly Accelerated Life Test.
Capnography, toxic gas detection, and air quality monitoring are just some examples of the areas in which infrared sources (IRS) can be found. They are used in numerous devices which are required to stand the test of time in medical, industrial, or environmental applications.
This require more than just the individual components working in perfect harmony – first and foremost, the device manufacturers need to be sure of the reliability of these components.
Added Value From the HALT for Axetris Customers
The HALT is what is known as a “test-to-failure”, and evaluates both the operating limits (reversible, “soft” faults) and the destruction limit (non-reversible, “hard” faults). This load limit test method is specifically designed to seek out faults. As a result, the loads to which the sources are exposed exceed the ambient conditions that are intended for later operation. The aim is to detect potential weak points at an early stage and analyze them extensively so that any defects that have arisen can be rectified while the product is still in the development stage. This increases reliability during the product's useful life and when it is subject to wear and tear, ensuring that Axetris' customers only receive infrared sources with a high degree of durability. Furthermore, the knowledge acquired from the tests flows directly into the Research and Development department. This ensures that customers will still be able to count on receiving high-quality IRS solutions in the future.
How Does the HALT Work?
The HALT involves subjecting IRS to thorough testing with regard to vibrations, temperature, and changes in temperature. In the HALT chamber, the test specimens are cooled with liquid nitrogen and heated using hot air from heating coils. To do this, the sources are fixed to a vibrating table in the chamber. The pneumatic hammers under the table create vibrations in all three directions up to an acceleration level of 50 Grms.
The sources are in operation over the entire duration of the test and are constantly monitored. To start with, they are subjected to a little stress. This is then increased gradually. Starting at the ambient temperature of 20°C, the temperature is gradually reduced during the cold step test until the lower operating limit of ‑100°C is achieved. The effect of evaporating liquid nitrogen is used for cooling. A similar procedure forms the basis of the hot step test. In this case too, the stress test starts at a non-critical room temperature. The temperature is gradually increased to the upper operating limit of 200°C. During the subsequent thermal shock test, checks are performed to identify whether the sources are still able to work correctly even in the event of sudden temperature changes. This is followed by a vibration test, during which the sources are subjected to stress in the form of increasing vibration. Finally, the sources are subjected to a combined environmental test, which involves stages of vibration plus temperature cycles.
The test is stopped as soon as the prototype reaches its operating limit or the limit of the HALT chamber is achieved. Axetris' EMIRS 50 was able to reach the HALT chamber's limit without demonstrating any weak points.
Intensive tests during the development and production stages are a requirement for infrared sources of highest quality. Axetris provides its customers with information about the relevant operating limits resulting from the HALT in technical data sheets.