Sometimes you may see some peeling on the top layers of Film Capacitors, as shown below, after the washing process at the manufacturing line.
This kind of delamination problem happens when the capacitors are subjected to excessive mechanical stress with blushing or flushing in the washing process (after soldering process), or similar processes. In order to prevent any performance deterioration with this delamination, some suppliers like Panasonic make their film capacitors (e.g. ECH-U1H104J) with over fifty layers of protective films on both the top and bottom sides of the capacitor element. This capacitor element does not deteriorate with this type of surface delamination. Therefore its electrical and reliability characteristics will not be affected even if all of the delaminated protective films are peeled off.
To verify the long term reliability of the capacitor with delamination problem, you can perform the following tests:
- High Temperature Loading Test
- Moisture Resistance Loading Test