What test plan is used for reliability qualification and acceptance testing?
Reliability testing is a variety of tests conducted to understand, evaluate, improve and analyze the reliability level of equipment. It aims to expose potential defects of equipment and obtain relevant equipment reliability by simulating the stress conditions in the actual working environment of the equipment. Characteristic information to improve and verify the reliability level of equipment.
Therefore, any test or experiment related to equipment failure, failure effects and reliability improvement can be considered a reliability test. During the entire life cycle of equipment, its reliability is not only affected by the design and manufacturing stages, but also by management level and testing capabilities. Equipment reliability testing plays a vital role in ensuring that the reliability of equipment meets the design reliability requirements.
Reliability qualification test and reliability acceptance test are common test types in reliability testing. Reliability testing is a means of investigating, analyzing and evaluating the reliability of products. Reliability tests can generally be divided into engineering tests and statistical tests.
Engineering tests include: environmental stress screening tests and reliability growth tests.
Statistical tests include: reliability qualification tests and reliability acceptance tests.
Engineering tests are generally less used. Among them, environmental stress screening is used to stimulate the inherent faults of products in the early stage of research and development. In the early stages of military electronic product development, more reliability identification tests and reliability acceptance tests are used.
In the actual product development process, the most commonly used statistical test is reliability identification or reliability acceptance test.
Reliability qualification test: mainly to determine whether the product design meets the specified reliability requirements. It is usually in the finalization stage of product design.
Reliability acceptance test: It is whether the mass-produced products can meet the specified reliability requirements under the specified environmental stress conditions and specific working conditions. It mainly assesses whether the reliability of batch-produced products decreases with changes in processes, tooling, components, parts, etc. during production.
The test plan needs to be determined before the reliability acceptance test experiment. It should simulate the actual use conditions as realistically as possible, and the applied reliability test stress is the same as the reliability qualification test. If a fault occurs during the test, only repair or replacement is allowed, and improvement measures are not allowed. Whether a reliability acceptance test is required is generally proposed by the purchaser. Generally used in product finalization or mass production R&D stages.
What test plan is used for reliability identification and reliability acceptance testing:
1. Timed censoring test: Specify the test time in advance. Once the test deadline is reached, the test will be terminated immediately and the number of failures will be recorded.
2. Fixed number truncation test: The allowed number of faults r0 is specified in advance. Once r0 faults occur, the test is terminated immediately and the test time t is recorded.
3. Sequential censoring test: According to the pre-planned time line for acceptance, rejection and censorship, the products under test are continuously observed and compared during the test, and decisions of acceptance, continued testing, or rejection are made at any time according to the criteria. Decide.
4. Full test: Conduct reliability test on every product in a batch.
It should be noted that when we usually do reliability appraisal or reliability acceptance testing, the most commonly used ones are timed truncation and sequential ending.
What are the test results of the reliability qualification test and reliability acceptance test?
According to the test plan, whether to accept or reject is determined after the test, reflecting the minimum lower limit of MTBF of the product.
Do reliability qualification tests and reliability acceptance tests require confirmation of fault criteria in advance?
The fault criteria need to be confirmed in advance and reflected in the test outline. This is an important part of reliability qualification or acceptance testing, and it also allows testers to identify the cause of product failure and compliance requirements.
