STS Testing (Shenzhen) Technology Co., Ltd.
Reliability test definition -- the activity undertaken to evaluate the maintenance of functional reliability of a product over a specified life period in all environments, including expected use, transportation, or storage.
Test categories: climate, power, outdoor environment, design verification test, etc.
First, climate test
1. Temp./ moisture-damp Heat Test
In general, the Dry heat test, Cold test, Constant Temp./Humidity steady state test and Humidity cycling test will be separately tested and verified.
For plastic materials, PCB, PCBA porous materials or finished products, such as all kinds of different materials have different forms of temperature and moisture physical reaction, the temperature Effect of plastic deformation or product produced by temperature (Over Heat) or bad start at low temperature (Cold start), etc., porous material will be wool stoma in humidity environment Effect (Breathing Effect) and surface moisture adsorption, infiltration, the case such as condensation, in a low humidity environment due to electrostatic charge build-up Effect induced failure products.
In addition to the outdoor products having to perform the Condensation test, the Condensation of indoor products should be avoided during the humidity test, and the failure of the product may occur due to the short-circuit of the product circuit caused by Condensation.
Common adverse humidity phenomena:
Loss of physical strength,
Changes in chemical properties,
Degradation of insulating material properties,
Electrical short circuit, oxidation corrosion of metal materials,
Loss of plasticity, acceleration of chemical reactions,
Degradation of electronic components, etc.
2. Dry Heat Test
Consumer electronics: +35℃~+45℃
Network communication products and industrial products: between +45℃ and +55℃,
Long-term outdoor use: more than +70℃
Vehicle electronics: depends on its installation conditions.
In the application, it is usually divided into High Temperature Storage Test and High Temperature Operating Test. In the Storage High Temperature Test, it is recommended to use the normal Temperature/High Temperature cycle Test, while the operation High Temperature Test is usually carried out by the steady-state High Temperature method.
Common high-temperature adverse phenomena of products:
Different expansion coefficients of materials cause parts to be damaged/stuck
Poor heat dissipation causes overheating electrical failure of parts
Belt relaxation, accelerated aging and color degradation, yellowing
Plastic softening, efficiency reduction, characteristic change, latent damage, oxidation and other phenomena.
3. Low temperature test
Consumer electronics: +5℃~ -5℃,
Network communication products and industrial products: between -5℃ and -20℃,
Long-term outdoor use products (such as LED street lamp) : -30℃ or-40℃
Cold start test is strongly recommended for operating low temperature test, as most products fail to start power at low temperature. It is better if the low temperature test can be carried out together with the minimum working voltage of the product.
4. Walk-in temperature and humidity test
Large temperature and humidity test (walk-in chamber)
For large electronic products, large packing materials (such as pallet) and large sample life test (MTBF), large test cabinets are required to meet the space requirements.
5. Temperature/altitude test (air pressure reduction)
The main purpose of the temperature/high altitude (low pressure) composite test is to simulate the air transport environment without pressure control, avionics, products with high pressure, motor or air tightness considerations, and products installed in high latitude countries. It is the most common phenomenon that thermal stress concentration occurs in products under Low Air Pressure, resulting in local temperature rise and function failure, as well as Arcing/ Corona of unstable motor operation and high-pressure components.
Common adverse phenomena of temperature/pressure:
Thermal effect/local overheating leads to material deformation or electrical failure, liquid/gas leakage, gas tightness failure, sealing vessel deformation/fracture, motor/engine operation instability, Arcing/ Corona, etc.