PCB aging testing (also called life testing or reliability testing) evaluates a PCB’s long-term performance and durability under extended operating conditions—simulating years of use in a compressed timeframe. Unlike environmental testing (which focuses on short-term stressors like vibration or temperature), aging testing applies continuous or cyclic stress (e.g., temperature, voltage, humidity) for hundreds or thousands of hours, identifying gradual failures (e.g., component degradation, solder joint fatigue, insulation breakdown) that only appear over time. This test is critical for PCBs in long-lifespan applications (e.g., automotive, industrial control, medical devices), where products are expected to operate reliably for 5-20 years.

The PCB aging testing process follows three key stages, based on industry standards (e.g., IEC 60068-2-1, IEC 60068-2-30): 1) Test Design & Stress Selection: Define stress parameters based on the PCB’s application and expected lifespan. Common stressors include: - Temperature Cycling: Alternating between high and low temperatures (e.g., -40°C to 85°C) for hundreds of cycles (e.g., 1000 cycles), simulating daily or seasonal temperature changes. This accelerates solder joint fatigue and trace cracking. - Humidity & Temperature (THB Testing): Exposing the PCB to high humidity (e.g., 85% RH) and high temperature (e.g., 85°C) for extended periods (e.g., 1000 hours), simulating tropical or industrial environments. This tests insulation resistance and prevents moisture-induced short circuits. - Power Cycling: Turning the PCB’s power on and off repeatedly (e.g., 10,000 cycles), simulating daily use and accelerating component degradation (e.g., capacitor aging, semiconductor wear). For automotive PCBs, power cycling includes voltage fluctuations (e.g., 9V to 16V) to replicate vehicle battery behavior. 2) Test Setup: Mount the PCB in an environmental chamber (capable of controlling temperature, humidity, and pressure) and connect it to a test system that: - Supplies power and input signals (e.g., sensor data, communication signals) to keep the PCB operating under normal conditions. - Monitors key parameters in real time (e.g., voltage, current, signal integrity, functional performance) using a DAS. For example, a power management PCB would have its output voltage monitored continuously—any deviation from 3.3V ±5% triggers an alert. 3) Test Execution & Data Collection: Run the aging test for the predefined duration (e.g., 1000 hours of THB testing), with periodic performance checks (e.g., every 24 hours). Collect data on: - Performance Drift: Gradual changes (e.g., increasing capacitor ESR, decreasing resistor precision) that indicate component aging. - Failure Time: The time at which the PCB fails to meet specifications (e.g., a solder joint opens, a signal is lost). Use this data to calculate the PCB’s “mean time to failure (MTTF)” and estimate its real-world lifespan (e.g., 1000 hours of THB testing ≈ 5 years of use). 4) Post-Test Analysis: After the test, perform a comprehensive evaluation: - Electrical Testing: Run functional tests, continuity tests, and impedance tests to verify performance. - Physical Inspection: Use a microscope or X-ray to check for damage (e.g., cracked solder joints, lifted pads, capacitor bulging). - Root Cause Analysis: For failed PCBs, identify the root cause (e.g., “capacitor aging due to high temperature” or “solder joint fatigue from temperature cycling”) and update the design (e.g., using high-temperature capacitors, improving solder joint geometry).

An industrial control manufacturer reported that aging testing identified a capacitor degradation issue in their PCBs—capacitors failed after 800 hours of THB testing, leading to a design change to use high-temperature, long-life capacitors. This reduced field failures by 70% over the PCB’s 10-year expected lifespan. For PCBs in safety-critical applications (e.g., medical imaging equipment), aging testing is required by regulatory bodies (e.g., FDA) to ensure patient safety and product compliance.