Defect Description
Press fit pins (pressure inserted pins that are not intended to be soldered [1]) that are bent, twisted, of irregular heights or other situations that result in irregular contacts (too loose or too tight) of the connector.
Defect Formation Process(s)
One possible cause of bent or twisted pins is damage during handling and insertion of a mating connector. Irregular heights of mating pins can be a result of manufacture variations.
|
List of Tests to Precipitate this Defect |
Failure Acceleration |
Likelihood to Precipitate this Defect (condition) |
Failure Mechanism(s) |
|
Random Vibration (RS/ED) |
• Random Vibration accelerates fatigue of irregular contacts • Random Vibration can cause fracture of irregular contacts |
✔/✇ |
Mechanical fatigue/ overstress |
|
Combined Environment |
• Same as Random Vibration |
✔ |
|
|
Thermal Shock |
• Cyclic thermal mechanical stress accelerates crack initiation and growth due to CTE mismatch • Thermal mechanical stress can cause fracture of the contacts |
✇ |
Thermal Fatigue Thermal Mechanical Overstress |
|
Bend Test |
• Bending can cause fracture of irregular contacts |
✇ (Defect at a location with significant strain due to bending) |
Mechanical overstress |
[2]
References
[1] IPC, Acceptability of Electronic Assemblies, IPC-A-610H, 2010
Permission for pictures
[2] IPC, Acceptability of Electronic Assemblies, IPC-A-610H, 2010.
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