Reliability testing of electronic products establishes the reliability characteristics of a product when operating or stored in various environmental conditions, providing useful data for use, production and design, and revealing problems in design, raw materials and process flow. Through failure analysis, quality control and other feedback measures, these problems can be resolved step by step and product reliability improved.

1. Main categories of reliability testing

(1) Climatic tests: high and low temperature tests, alternating high and low temperature tests, rapid temperature change tests and ingress protection tests.

(2) Salt mist tests: neutral salt mist, acid salt mist, copper accelerated salt mist, cyclic salt mist and alternating salt mist.

(3) Mechanical tests: vibration testing including random vibration and sweep vibration, mechanical shock testing, drop testing and combined three-axis testing.

(4) Mechanical system performance tests: tensile performance, flexural performance, compressive performance and pendulum impact.

(5) Thermal performance tests: heat deflection temperature, Vicat softening point and melt index.

(6) Electrical system performance: dielectric strength, insulation resistance, contact resistance and voltage drop.

(7) Material tests: xenon lamp ageing, fluorescent lamp ageing, Shore hardness, pencil hardness, chemical resistance, colour difference, gloss, adhesion and adhesion.

2. How reliability testing is classified

(1) By environmental condition, testing can be divided into simulated testing under various stress conditions and on-site testing.

(2) By test item, it can be divided into environmental testing, life testing, accelerated testing and various special tests.

(3) By purpose, it can be divided into screening testing, qualification testing and acceptance testing.

(4) By nature, it can be divided into destructive and non-destructive testing.

3. Typical temperature tests

Lower temperature limit operating test. The sample is first powered up and run through the test program for an initial check. With the sample not operating, the chamber temperature is gradually lowered to 0℃ and, once stable, the sample is powered and the program run for 5 hours; function and operation shall be normal. After the test the sample is returned to room temperature, removed and allowed to recover for 2 hours at normal atmospheric pressure. Recommended criteria: function and operation normal, with no obvious appearance deviation.

Low temperature storage test. The sample is placed in a low temperature chamber, the chamber is lowered to -20℃ and the sample stored unpowered for 16 hours. It is then removed, returned to room temperature and allowed to recover for 2 hours before being powered and run through the test program. Function and operation shall be normal with no obvious appearance deviation. To prevent frost and condensation the sample may be sealed in polyethylene film, with a desiccant inside the sealed bag if necessary. Recommended criteria: function and operation normal, with no obvious appearance deviation.

Upper temperature limit operating test. The sample is first checked. With the sample not operating, the chamber is gradually raised to 40℃ and, once stable, the sample is powered and the diagnostic program run for 5 hours; function and operation shall be normal. After the test the sample is returned to room temperature, removed and allowed to recover for 2 hours at normal atmospheric pressure. Recommended criteria: function and operation normal, with no obvious appearance deviation.

High temperature storage test. The sample is placed in a high temperature chamber, the chamber is raised to 55℃ and the sample stored unpowered for 16 hours, then removed, returned to room temperature and allowed to recover for 2 hours. Recommended criteria: function and operation normal, with no obvious appearance deviation.

In practice the procedures vary with product attributes and the operating environment, so additional or alternative items may be selected according to product characteristics and the specific environment and method of use, in order to verify whether the product can work effectively over the long term.