In reliability testing, it is common to encounter double 85 testing, especially for electronic products. Is double 85 testing an environmental adaptability test or a reliability test?
Environmental testing and reliability testing are two different types of testing. Environmental testing, also known as environmental adaptability testing, results in Pass (the product can adapt to the most extreme harsh environment in nature after being launched on the market) and Fail (the product cannot adapt to the most extreme harsh environment in nature after being launched on the market). And reliability testing, which is easy to understand, is to test the reliability R (t) of the product. Simply put, after the test is completed, a conclusion can be drawn about the reliability at time t.
If it is used as a verification material, sealing, PCB coating, capacitor, plastic, connector, etc. to evaluate their resistance to moisture and high temperature, and to check for oxidation, corrosion, moisture absorption deformation, material aging, and other issues, the 85 test can be used as an environmental test. If it is to evaluate the reliability of electronic components under wet, high temperature, and working conditions, then it should be used as a reliability test. That is to say, testing depends on your experimental purpose.
Why 85 instead of any other data? In fact, this "85/85" combination is actually a product of long-term industry experience and standard consensus, with scientific and engineering rationality: 85 ℃ is close to the thermal stability limit of plastic materials, soldering, sealants, etc., but it will not cause hot melting or warping too quickly. The humidity is 85% RH, close to the edge of maximum air saturation (more than 90% prone to condensation), but it can still maintain a continuous humid and hot environment rather than a water droplet state, making it easier to control experimental repeatability.
Double 85 testing plan
·For the purpose of climate and environmental adaptability testing:
Reference standards: IEC 60068-2-78, JEDEC JESD22-A101;
Testing time: 96-240 hours;
Sample size: 3-5 pieces
During the experiment: Do not turn on (simulate shutdown for transportation and storage)
Test result judgment: 1 No obvious abnormalities in appearance (no cracks, bulges, corrosion); 2. Function testing returns to normal; 3. After the optical and electrical performance is restored, it meets the requirements of the specification sheet
Test result: Pass (packaging structure, moisture-proof design qualified) or Fail (both must be judged as Fail)
·As the purpose of reliability testing
Reference standard: JESD22-A110
Testing time: 500~1000 hours
Sample size: greater than 10+, usually 20+
During the experiment: Start up and run
Stress: In addition to temperature and humidity double 85, voltage bias (THBTest) can usually be increased
During the entire experiment: Start up and run
Processing of experimental results: using an extended extended Peck model.

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