The implementation of SMT, the performance of aging that patch capacitance crack, crack position is from the starting point to the substrate electrode electrode position starting point slope, 45 degree direction, suppliers say external pressure caused by the master, ask who knows? How should I prove it? Details of the method can be added to the score.This is the appearance of cracking.There is also another symptom, the appearance of which shows no cracking, but there are cracks, cracks and symptoms in the same first symptoms
Minimize the bending of the circuit board, reduce the stress of the ceramic chip capacitor on the circuit board, and reduce the mechanical stress caused by the difference between the thermal expansion coefficient of the ceramic chip capacitor and the circuit boardDue to mechanical stress can be slowed by selecting the capacitor package size small ceramic capacitor and the circuit board to reduce the difference in coefficient of thermal expansion, such as aluminum board should be used less than 1810 of the package, if the solution method can be used not only the capacitance in parallel or by lamination can also be used. The ceramic capacitor package with pins.
When the ceramic chip capacitor is mechanically broken, the electrode insulation spacing at the fracture will be lower than the breakdown voltage, which will cause an arc discharge between two or more electrodes, and completely damage the ceramic chip capacitor
The main failure modes of SMD ceramic capacitors are fractureChip ceramic capacitors for common failure is broken, this is the chip ceramic capacitor medium itself. The decision of brittle chip ceramic capacitors directly welded on a circuit board, all kinds of machinery from the circuit board directly under stress, and lead type ceramic capacitor can be absorbed from the circuit board by mechanical lead stress. Therefore, the chip ceramic capacitors, because of different thermal expansion coefficient or circuit board bending caused by mechanical stress is the main factor of chip ceramic capacitor fault.
