It turns out that the HALT & HASS tests have quietly become a valuable assistant for automotive companies! Would you like to know how it serves the automotive industry?
Release time:
2022-04-13 12:12
Source:
Recently, the company's reliability product department is vigorously organizing the "Smart Measurement Technology Sharing Series Lecture on HALT&HASS (Efficient Reliability Process) Online Seminar". As a novice in reliability technology, I have unknowingly been influenced a bit! I always thought thatHALT&HASS testingwas the darling of military enterprises, aerospace companies, and some research institutions. Who would have thought that it has now transformed into a powerful assistant for automotive companies, making one marvel: technology is truly a pioneer with overwhelming power, without seeing any swords or blades, yet it has already changed the vitality of the nine provinces! My colleagues are too busy to help me catch up on the knowledge.HALT&HASS testingThe magic of technology, I found an articleHALT&HASS testingapplied in the automotive field, to understand it myself (it is an article written by a master from an automotive parts laboratory, for those who are afraid I might misrepresent it, you can read it at this website: www.autotest-lab.com/). Below are some key points from the article, let's digest them together!
The competition in automotive electronics is becoming increasingly fierce, leading automotive electronics to develop towards high reliability, high technological content, and high added value. Automotive consumers are raising increasingly strict requirements for the product quality of cars and various electronic products inside the car. How to ensure the normal operation of advanced and complex cars and various electronic devices inside the car has become a focal issue for global electronic manufacturers.
Every product has its defects, and when these failures occur, the product often exceeds its validity period, especially for electronic products used in cars, such as DVD players, car audio systems, multimedia reception systems, etc. If problems hidden in these electronic products cannot be discovered and resolved early, and instead wait until they are assembled into the car, allowing the user to use it for a period of time before the problems slowly emerge, it will cause great losses to manufacturers and users. To solve problems, one must first identify where the problems lie. By increasing external environmental stress and forcing failures to be exposed early, it is an effective method for early detection and resolution of issues.
Currently, the commonreliability testingmethods for domestic automotive electronic products generally use traditional performance varying temperature and humidity chambers during R&D to verify and improve product reliability; the traditional testing method used in online production is aging life (i.e., high temperature, etc.). Relying solely on these traditional testing methods, it is still somewhat difficult to achieve the high-quality technical indicators of foreign automotive electronic products.
HALT (Highly Accelerated Life Test,High Accelerated Life Test) & HASS (Highly Accelerated Stress Screening,High Accelerated Stress Screening) is an effective testing method and equipment that can improve product reliability.
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♦Application of HALT&HASS reliability testingHALT & HASS is a testing method derived from the U.S. military for design quality verification and manufacturing quality verification, and has now become the standard product verification method in the U.S. electronics industry. It shortens the new product reliability testing that originally took 6 months to a year to just one week, and the product issues discovered in this week are almost consistent with the problems found by customers after application. Therefore, the HALT & HASS testing method has become a necessary verification before the launch of new products. Outside the U.S., many international 3C electronics manufacturers also use the same or similar methods to enhance product quality.
1. HALT
HALT is an experimental method that discovers design limitations and potential weaknesses by subjecting the tested object to different stresses. The main purpose of HALT is to increase the limit values of the tested object, thereby enhancing its robustness and reliability. HALT applies step stress to the product, which can early detect product defects, operational design margins, and structural strength limits. The stresses applied to the product include vibration, high and low temperatures, temperature cycling, power switch cycling, voltage margins, and frequency margin tests. This testing can quickly identify defects in product design and manufacturing, improve design flaws, increase product reliability, and shorten its market launch cycle, while also establishing foundational data for design capability and product reliability, which is important for future R&D.
In simple terms, HALT consists of continuous testing, analysis, verification, and correction, with the key being to analyze the root causes of all failures.
The main testing functions of HALT are as follows:
* Use high environmental stress to stimulate and improve product design defects;
* Understand the product's design capability and failure modes;
* Serve as a reference for high-stress screening and specification auditing;
* Quickly identify flaws in the product manufacturing process;
* Increase product reliability and reduce maintenance costs;
* Establish a product design capability database to provide a basis for R&D and shorten the design and manufacturing cycle.
HALT is applied in the product development stage, allowing for early detection of weak links in product reliability. The stresses applied are far higher than those experienced by the product during normal transportation, storage, and use.
HALT includes the following content:
* Gradually apply stress until the product fails or malfunctions;
* Take temporary measures to correct the product's failure or malfunction;
* Continue to gradually apply stress until the product fails or malfunctions again, and correct it again;
* Repeat the above stress-failure-correction steps;
* Identify the basic operational limits and basic destruction limits of the product.
2. HASS
HASS is applied in the production stage of the product to ensure that all improvements found in HALT can be implemented. HASS also ensures that new defects are not introduced due to changes in the production process and components.
HASS includes the following content:
* Conduct pre-screening to eliminate potential hidden defects that may develop into obvious defects;
* Conduct detection screening to identify obvious defects.
* 进行探测筛选，找出明显缺陷；
* Fault analysis;
* Improvement measures.
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♦Application of HALT&HASS reliability testingSteps
HALT is an experimental method that discovers design limitations and potential weaknesses by subjecting the tested object to different stresses. The main purpose of HALT is to increase the limit values of the tested object, thereby enhancing its robustness and reliability. HALT applies step stress to the product, which can early detect product defects, operational design margins, and structural strength limits. The stresses applied to the product include vibration, high and low temperatures, temperature cycling, power switch cycling, voltage margins, and frequency margin tests. This testing can quickly identify defects in product design and manufacturing, improve design flaws, increase product reliability, and shorten its market launch cycle, while also establishing foundational data for design capability and product reliability, which is important for future R&D.
HALT is divided into four main test processes, namely:
* Temperature stress;
* High-speed temperature conduction;
* Random vibration;
* Combined temperature and vibration stress.
In the HALT test, the operational limits and failure limits of the tested object under temperature and vibration stress can be found. The equipment used for this experiment is the OVS Combined Stress System designed by QualMark, with a temperature range of -100℃ to +200℃, a maximum temperature change rate of 60℃/min, and a maximum acceleration of up to 60Grms. The design combines the vibration machine and temperature chamber to apply temperature and vibration stress to the tested object simultaneously. The following describes the general situation of the four test processes:
1) Temperature stress: ★★★
2) High-speed temperature conduction: ★★★
3) Random vibration: ★★★
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4) Combined temperature and vibration stress: ★★★
Record any abnormal conditions of the tested object in the above four test processes, analyze whether these issues can be overcome by design changes, and modify them before proceeding to the next step of testing. By improving the operational limits and failure limits of the product, the goal of enhancing reliability is achieved.
HASS is applied in the production stage of the product to ensure that all improvements found in HALT can be implemented. HASS also ensures that new defects are not introduced due to changes in the production process and components.
The purpose of applying HASS is to quickly identify whether there are production quality risks in mass-produced finished products. This test includes three main test processes:
* HASS Development (HASS test planning phase);
* Proof-of-Screen (planning verification phase);
* Production HASS (HASS execution phase).
The following describes the testing process for general electronic products:
The HASS test plan must refer to the results obtained from the previous HALT test. Generally, the operational limits of high and low temperatures in the combined temperature and vibration stress are reduced by 20%, while the vibration conditions are set to 50% of the failure limit G value as the initial condition for the HASS test plan. Then, based on this condition, the combined temperature and vibration stress tests are executed, observing whether any faults occur in the tested object. If faults occur, it must first be determined whether they are caused by excessive environmental stress or by the quality of the tested object itself. If it is the former, the temperature and vibration stress should be relaxed by 10% for retesting; if it is the latter, it indicates that the current testing conditions are effective. If no faults occur, the environmental stress must be increased by 10% for retesting.
2) Proof-of-Screen
When establishing the HASS Profile (HASS program), two principles should be noted: first, it must be able to detect potential hazards that may cause equipment failure; second, it should not cause equipment damage or 'internal injuries' after testing. To ensure that the results obtained in the HASS test planning phase meet the above two principles, three test samples must be prepared, and some defects that are not manufactured or assembled according to standard processes should be created on each sample, such as floating parts, cold solder joints, and improper assembly. The conditions obtained from the HASS test planning phase are used to test each sample, observing whether the artificial defects on each sample can be detected, to determine whether to tighten or relax the testing conditions, so that the HASS Profile achieves the expected effect.
After completing the effectiveness test, new test samples should be tested 30 to 50 times under the adjusted conditions. If no damage occurs due to improper stress, it can be determined that the HASS Profile has passed the planning verification phase test and can be used for Production HASS. Conversely, the testing conditions must be reviewed and adjusted to obtain the best combination.
Any HASS Profile that has passed the Proof-of-Screen test is regarded as a fast and effective quality screening tool, but it must also be adjusted based on feedback from customers after using the product. Additionally, when design changes occur, the testing conditions should be modified accordingly.
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♦ Conclusion
HALT & HASSreliability testing technology has received widespread attention and recognition in the domestic and international electronics industry. It allows designers and manufacturers to analyze and improve the problems that occur during testing, giving them full confidence in product quality.
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