What is HALT testing?
HALT testing helps product designers to find potential defects in a new product before it goes into mass production:
- A few prototypes are subjected to a simulation based on their typical use. For example, if the product is a door lock, it is locked and unlocked thousands of times, with an automated arm applying the same pressure as typical fingers.
- That test is usually done in a specialized environmental chamber in a lab. Various environmental test stimuli are applied to the prototypes (such as vibration, humidity, temperature, thermal cycling, over-voltage, etc) in a bid to find product design and fabrication process flaws.
These stresses will ultimately reach a level a lot higher than the product may reasonably be expected to experience during normal operation, as the test’s objective is to push the product’s operational and destruction limits. The purpose is to continue until failure!
When a ‘failure mode’ is found too early, a new prototype is designed which fixes it, and then another round of HALT testing begins again until the final prototype is arrived at which has no serious design or fabrication process problems and is ready for production.
HALT is also a good complement to a design FMEA analysis. Both are preventive measures. If you intend to make many units of your product, you certainly want to do both.
The HALT process
This repetitive testing process is clearer when you examine this diagram:
What HALT helps us to find
Your HALT test will uncover:
- Failure modes (in the design or production process) and their root causes
- Realistic functional operating limits for the product
- How far the product can be pushed until it is destroyed
HALT testing standards
There is no specific HALT testing standard because it depends on the device being tested’s individual characteristics.
You will find a HALT component to certain standards relevant to the product or component being tested or certain manufacturers also have their own as you can see here from GM.
IEST-RP-PR003: HALT AND HASS also provides some generic information about the testing to be conducted.
Good to know
- Originally developed for electronics containing printed circuits, HALT can be used to test almost any product or component type if a suitable process can be put in place that uncovers failure modes.
- Although this is a test to destruction, only a few samples are required.
More reliability tests to read about
Listen to more discussion about reliability testing
We also discuss why importers need reliability testing in this episode of our podcast, covering, among other things, what this type of testing is, when we carry it out, what are the risks of not performing it, and what it costs: