Why are there bubbles when electrophoretic paint is painted after painting?

There are bubbles in the bath solution, indicating that the outside air has entered the paint solution through some channels. The analysis reasons are as follows:

1) When the coated workpiece enters the tank, some air is not excluded.

2) The voltage is too high, the electrolytic reaction is fast and there are too many bubbles.

3) There is an air source in the paint liquid circulating stirring system.

2. Electrophoresis line process flow

Pre-cleaning, online degreasing, primary water washing, secondary water washing, phosphating, tertiary water washing, circulating deionized water washing, electrophoretic coating, tank washing, primary ultrafiltration water washing, secondary ultrafiltration water washing, clean ultrafiltration water washing, drying and off-line.

3. Failure phenomenon

Bubbles are generated on the surface of the paint solution in the electrophoresis tank, and the working paint film after electrophoresis is uneven, with poor appearance and orange peel in some parts.