Problems that should be paid attention to in accelerated test

　　The role of accelerated life test is: it can speed up the test process; through the harsh condition test, the safety margin of switch adapter products and electronic components can be determined, and the components with low reliability can be eliminated and screened; observed under severe conditions The life value (or failure rate) of this value, there is a certain regularity between the value and the life value under normal conditions. Using this regularity, the life value under normal conditions can be predicted. Because the accelerated life test is a test under severe conditions, it is very different from the normal use conditions of switch adapters or electronic equipment. Therefore, when performing accelerated life tests, the following requirements should be paid attention to in order to The switch adapter makes a correct evaluation.

　　1. Compared with the normal conditions, the accelerated test should not change the basic mode and mechanism of failure, or change their relative advantages. Determine and select the scale, time and conditions of the accelerated life test according to the end use of the switch adapter adapter, and determine the test parameters according to the purpose and requirements of the accelerated life test. Such as test time, failure rate, mean time between failures (MTBF), time history changes and limit values, etc. But it should be particularly emphasized that during the test, the failure mode and failure mechanism of the switch adapter should not be changed.

　　2. The stress level of the accelerated life test should be greater than the working stress specified in the design. When different stress loads exist at the same time, consideration should be given to whether they can be applied at the same time, whether they can be controlled, and whether they can be measured stably. In the actual application of switch adapter products, the combination of environmental stresses that may be encountered is unpredictable. For example, in the accelerated life test of switch adapter products, instantaneous distribution voltage peaks and adapter conversion voltage fluctuations may sometimes reach several times the normal voltage. This is caused by consideration of lightning and electrostatic discharge. Influence. The stress level of the accelerated life test should be strict enough to eliminate the unreliable structure and potential unreliable parts of the switch adapter. At the same time, considering the requirements of system reliability, the test stress should not be too high, so as not to induce the original failure of the switch adapter. Other failure mechanisms. In addition, environmental stress conditions, such as temperature, humidity, vibration, shock, dust, and harmful chemical gases, should also be moderate.

　　3. In a given time, the selected condition should be able to fail earlier than other acceleration conditions. Under the conditions of meeting the experimental requirements, the time of the accelerated life test should be as short as possible, but the time should be sufficient, especially for the accelerated life test of new products. The time should not be shorter than the depletion failure period.

　　4. The test equipment and monitoring devices must be carefully managed, reliable, and accurate to maintain their normal functions and maintain the stability of the test conditions, because the test device itself sometimes fails before the test object, which causes the test conditions. Changes, and even affect the normal conduct of the test work.

　　5. Do a good job in software management and progress control of records, manuals and data collection and analysis. The data record of the test must be complete, no omissions or false, clear handwriting, and no alteration.

　　In addition, failures caused by test personnel or test equipment and failures caused by interference from external conditions should also be specifically recorded. The person in charge of the test technology should check the data records immediately and deal with any problems in time. In the middle of the test, when measuring special values to judge faults and aging, if continuous monitoring and control are not possible, the measurement interval should be specified. The storage of samples is an important task. For each sample, a file card must be established to record in detail the test time, cut-off time and frequency of failure.

　　As a special test in the reliability test, the accelerated life test itself does not improve the reliability level of the switch adapter adapter, it is only an important means to evaluate the reliability level of the switch adapter adapter. Through this test, the reliability of the switch adapter is determined, and whether it meets the requirements of the specified reliability index; whether the switch adapter can maintain the original reliability level or be improved; provide for the improvement of the reliability of the switch adapter Basis; to ensure that the factory products meet the user's reliability requirements; to provide data information for predicting the reliability of the switch adapter. Therefore, accelerated life test is an important test method of reliability test.

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