“The key core that affects product quality and user experience — the reliability of PCBA“
In the field of electronic manufacturing, the reliability of PCBA (Printed Circuit Board Assembly) directly relates to product quality and user experience. Below, let’s explore 5 commonly used methods for PCBA reliability testing.
Burn-in Testing
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Burn-in testing is based on the principle of “accelerated failure”. It simulates the actual working conditions of a product over a long period to accelerate the exposure of potential defects in the PCBA.Testing Method: During the test, functional PCBA boards that pass initial testing are placed in a temperature and humidity-controlled environment chamber, with temperatures typically set between 40℃-85℃ and humidity between 45%-95% RH. Operations such as cycling power on and off (3-5 times per hour), simulating functional operation (e.g., CPU under full load), and applying rated loads are performed continuously for 24-72 hours. During this process, monitoring circuit parameters (such as voltage fluctuations and signal attenuation) and component temperature changes can accurately identify issues like cold solder joints, capacitor leakage, and poor thermal stability of components. It is worth noting that while burn-in testing can comprehensively assess product stability, it incurs high energy costs. Therefore, companies often adopt a mixed sampling strategy: full inspection of the first piece + sampling of batches according to AQL standards, predicting the failure probability of the entire batch through big data analysis.
Vibration Testing
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Vibration testing simulates the mechanical environment of PCBA during transportation, aerospace, and other scenarios, using a vibration table to generate sinusoidal, random, or shock vibrations.Testing Method: During the test, the PCBA must be fixed to a fixture in its actual installation manner, with a frequency range covering 5-2000Hz and acceleration up to 50g. In sinusoidal sweep frequency testing, resonance may occur when the frequency approaches the inherent frequency of components, leading to issues like pin breakage and displacement of surface-mounted capacitors; random vibration is closer to real transportation environments and can expose hidden defects like solder fatigue cracks. To enhance testing effectiveness, companies often use a “three-axis testing method” (vibrating each of the X, Y, and Z axes for 2 hours) and combine it with metallographic microscopy to observe microscopic structural changes at the soldering interface.
Surge Impact Testing
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Surge impact testing aims to verify the PCBA’s tolerance to instantaneous overvoltage and overcurrent. The testing equipment simulates scenarios like lightning strikes and power grid switching, generating surge pulses with a waveform of 8/20μs, with voltage peaks reaching 6kV.
Testing Method: During the test, common-mode and differential-mode interference must be applied to the power and signal ports, respectively, while monitoring circuit responses with an oscilloscope. For example, a power circuit without a TVS diode may experience MOSFET breakdown under a 2kV surge; data lines without ESD protection can lead to signal integrity failure. Companies typically adopt a “graded testing method”, gradually increasing voltage from a low level (e.g., 1kV) to record failure thresholds and optimize circuit design using surge suppressors, isolation transformers, and other components.
Temperature and Humidity Cycling Testing
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Temperature and humidity cycling testing evaluates the environmental adaptability of PCBA by simulating extreme environmental changes.Testing Method: The testing process follows a cycle of “high temperature → low temperature → humid heat → drying”, such as -40℃→85℃→85℃/85% RH→25℃/45% RH, with each stage maintained for 2-4 hours and up to 50 cycles. During this process, stress caused by differences in thermal expansion coefficients can lead to solder joint cracking, while high humidity environments may cause surface leakage on PCBs and metal corrosion. Testing requires high-precision temperature and humidity chambers and data acquisition systems to monitor changes in insulation resistance and contact resistance in real-time. For outdoor equipment, companies may also add salt spray + temperature and humidity composite testing to simulate harsh environments in coastal areas.
Salt Spray Testing
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Salt spray testing is designed to expose the failure risks of PCBA in corrosive salt spray environments.
Testing Method: In the testing chamber, a 5% concentration NaCl solution is sprayed, maintaining a temperature of 35℃ to simulate marine and salt-laden industrial environments. After continuous spraying for 24-1000 hours, the corrosion of the metal layers on the PCBA surface (such as pins and pads) is observed, and the amount of metal loss is calculated using the weighing method, with X-ray fluorescence spectroscopy used to analyze changes in coating composition. For military and marine equipment, CASS (Copper Accelerated Salt Spray) testing is also required, with corrosion intensity three times that of ordinary salt spray. Companies typically adopt a “three-proof paint + metal protective layer” dual insurance strategy.
The above 5 testing methods ensure PCBA reliability from different dimensions and are currently the main means of testing. Companies can combine testing schemes based on product application scenarios. If you have other testing methods or operational details, feel free to leave a comment in the section below~~