Mechanism of Solder Joint Intermittent Faults and Its Detection

Aiming at intermittent fault detection problem that caused by solder joint under vibration stress, induced mechanism of solder joint intermittent fault is analysed and the detection method of solder joint intermittent fault number is studied. Firstly, theoretical analysis of the solder joint intermittent connection fault under vibration stress is conducted. Relationships between vibration stress parameters and intermittent faults are described. Dynamic characteristics of the solder joint are interaction between contact interface and vibration stress. However, within a finite time, dynamic parameter amplitude does not depend on the contact interface morphology, and the contact resistance is proportional to the acceleration, displacement and frequency. Next, the detection of solder joint intermittent connection fault is studied. Stimulus signal is selected and a detection algorithm is proposed. A continuous monitoring circuit detects the intermittent fault and DSP processor calculates the number of intermittent faults. Finally, a case study is conducted and a circuit board is used to test the intermittent fault detection method. Voltage change is detected by oscilloscope and the described method simultaneously. Test result shows the number of intermittent faults can be recorded correctly.