The reliability of electronic products is affected by many factors. Apart from human activity, the environment in which products are located is also an important factor in their failure. Among them, temperature, humidity and vibration are three important environmental factors that have the greatest impact on product properties.
1.The relationship between temperature, humidity, vibrational stress and failure
(1) Relationship between thermal stress and failure
Heat stress is one of the most important causes of product failure. It is usually caused by aging, accumulation of heat, migration and diffusion of high temperature, low temperature is broken by low temperature, and the expansion or packing of products caused by temperature cycling or temperature effect.
(2) The relationship between water pressure and failure
Humidity caused by high temperatures will also lead to product failure. In a cool place, the material will get moisture from the air, causing expansion, reduction in strength and change in function, which will reduce the electrical activity of the product’s equipment insulation, causing corrosion, short circuit and mold.
(3) Relationship between equipment vibration and failure
The movement of the vibration stress on the tool of the product will cause the tool of the product to move, causing fracture, separation, poor contact, wear, fatigue deformation, cracking and fracture of the tool of the product.
2.The relationship between the absolute speed of temperature, humidity and vibration and product failure
According to long-term research on the relationship between the three applications of temperature, humidity and vibration in product failure, it has been found that any of the three environmental stresses applied to the product can lead to product failure. . If all three environmental pressures are applied to the product at the same time, the probability of product failure increases from 3 to 5 times.
3.Application of temperature, humidity and vibration comprehensive test technology
(1) Vibration stress
During the equipment operation, select 24h for the vibration stress test, select 25% of the random duty cycle time to apply the noise stress, and the vibration cycle time starts from 3 o’clock in the morning.
(2) Temperature and humidity restrictions
1. The temperature during product testing should be controlled at 22 ℃ and 25%. Then start the test, first quickly reduce the temperature to -50 ℃ for 1.75h, then rise to -32 ℃;
2. Reduce the temperature to -34.5 ℃ in 3.25h;
3. Take 13 hours to raise the temperature to -28C:
4. Allow 5 hours for the temperature to rise to 22°C. Keep the temperature at 22 ℃ and adjust the humidity at 25% – 75%;
5. Raise the temperature to 25°C and 95% humidity within 2 hours:
6. Take 10h to raise the temperature to 29 ℃, and the humidity is constant at 95%;
7. Take 5h to reduce the temperature to 25 ℃ and at this time the relative humidity remains unchanged at 95%;
8. Reduce the temperature to 22 ℃ and the humidity to 25%-75% within 2 hours;
9. Raise the temperature to 25 ℃ and reduce the humidity to 65% within 2 hours;
10. Raise the temperature to 48 ℃ and reduce the humidity to 25% within 12 hours;
11. Increase the temperature to 60 ℃ and humidity to 95%. Keep it in this position for 2 hours, and then reduce the temperature to 48 ℃.
4.Application instructions of high temperature, humidity and vibration environmental test technology
(1) Product reliability improvement research technology
Product Reliability Strengthens Testing Technology in Temperature, Humidity and Vibration Full environmental testing can help experts understand the weak link of product design and service for various stress conditions, identify the cause of product failure e.g. according to the condition of the defect, and carefully examine the process and design, so as to strengthen the environmental flexibility and reliability of the product.
(2) The development process of high temperature, humidity and vibration environment test technology
Heat, humidity and vibration complete environmental testing focuses on finding and analysing weak links and potential defects in product design and manufacturing, and has become a testing technology that combines methods different jobs.
5.Conclusion
The comprehensive temperature, humidity and vibration test is able to restore the operating environment of the equipment, so as to use temperature, humidity and vibration changes to stimulate product defects and see the design and technical defects of the product, still remain good and important design and manufacturing process, so that the product can work in the environment with resistance and speed.
