Paint resistance The impurity ions brought into the electrophoresis tank from the previous process caused the resistance of the paint to decrease, which caused the paint film to appear rough, uneven and pinholes. In the painting construction, the paint needs to be purified. In order to obtain a high-quality coating film, cathode mask equipment can be used to remove ammonium, calcium, magnesium and other impurity positive ions.

The voltage electrophoretic coating adopts the constant voltage method, and the equipment is relatively simple and easy to control. The voltage has a great influence on the paint film; the higher the voltage, the thicker the electrophoretic paint film, which can improve the coating ability and shorten the construction time for the parts that are difficult to paint. However, if the voltage is too high, the surface of the paint film will be rough, and the phenomenon of "orange peel" will easily occur after drying. The voltage is too low, the electrolysis reaction is slow, the paint film is thin and uniform, and the swimming penetration is poor. The choice of voltage is determined by the type of paint and construction requirements. In general, the voltage is inversely proportional to the solid content of the paint and the paint temperature, and directly proportional to the distance between the two poles. The surface of steel is 40～70V, and the surface of aluminum and aluminum alloy can be used.

Electrophoresis time The thickness of the paint film increases with the extension of the electrophoresis time, but when the paint film reaches a certain thickness, continue to extend the time, and the thickness cannot be increased, but it will aggravate the side reaction; on the contrary, if the electrophoresis time is too short, the coating is too thin. The electrophoresis time should be based on the voltage used, and under the condition of ensuring the quality of the coating, the shorter the better. Generally, the electrophoresis time for workpieces is 1 to 3 minutes, and for large workpieces, it is 3 to 4 minutes. If the surface geometry of the coated object is complicated, the voltage and time can be increased appropriately.