The difference between reliability HALT experiment and HASS experiment
What is a HALT test?
HALT (Highly Accelerated Life Test) stands for Highly Accelerated Life Test. HALT is a testing method that accelerates the exposure of product defects and weak points by applying gradually increasing environmental stresses or working loads. Mainly used in the product development stage, it can expose product design and process defects in a short period of time, thereby providing a basis for us to make design improvements and improve product reliability.
HALT was first proposed by Hobbs in the United States and continues to be improved. The main purpose is to increase the limit value of the measured object, thereby increasing its robustness and reliability.
HALT applies stress in a step-by-step manner, which can quickly discover product defects, working limits and damage limits. The stresses it imposes on products include vibration, high and low temperatures, temperature cycles, power switching cycles, voltage margin and frequency margin tests, etc. This test can be used to quickly identify defects in product design and manufacturing, improve design defects, increase product reliability and shorten the time to market. It can also improve design and accumulate basic data on product reliability, providing important basis for subsequent product development.
What is the HASS test?
HASS (High Accelerated StressScreen) stands for Highly Accelerated Stress Screening Test. HASS is a highly accelerated stress screening done in the production stage after the product has passed HALT to obtain the working limit or damage limit value. Generally, 100% of the products are required to participate in the screening.
The purpose of HASS is to reduce potential defects in products and try to eliminate these defects before the products leave the factory. HASS mainly uses accelerated stress methods to find defective products in a short time and shorten the product improvement cycle.
HASS is applied during the production phase of the product to ensure that all improvements found in HALT can be implemented. HASS can also ensure that no new defects are introduced due to changes in production processes and components.
The difference between HASS and HALT:
1. The stages are different: HALT is the development stage, HASS is the early stage of production, or the production stage
2. Different purposes: HALT test is a bottom-up test, the purpose is to find shortcomings in the design and improve them, while HASS is a pass-through test and mass production quality control.
3. Different strengths: The HALT test may cause damage to the product, but the HASS test should not cause damage to the product, because after the HASS test, the product needs to be sold. Products after the HALT test are strictly prohibited from being shipped again.
4. The test methods are different: the HALT test accelerates stress until the product fails; the HASS test is a process that is repeated many times without product wear and gradually corrects to complete the test outline.
5. The HALT test and HASS test optimize the failure rate and are at different stages of the device life cycle.