Investigation of a short circuit due to a foreign body
Problem
A failure was reported by the customer due to a short circuit After a CT scan could one foreign body in an assembly. The foreign body was located in the area of the soldering and was metallic particle detected. The particle was recovered and cleaned for further analysis.
examination of the foreign body
The recovered foreign body was classified as metallic chip Chemical analysis showed that the chip consisted mainly of Zinc (Zn) and small amounts of Iron (Fe) This indicates that the origin of the particle is in a galvanized steel component lies.
cause of foreign body formation
Inside the housing galvanized steel bushings found on the inner radius material defects The surface morphology in the area of the discontinuities showed similar structures to that of the spanThis suggests that the discontinuities on the surface of the socket a favorable basis for the chip formation represent.
Conclusion
It is assumed that the metallic chip during a manufacturing process from the galvanized steel bushing and then got onto the assembly. The foreign body then caused damage through contact with the soldering now Kurzschluss.