Features of electrophoresis equipment

1. Electrophoresis time

The thickness of the paint film increases with the extension of the electrophoresis equipment 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 as short as possible under the condition of ensuring the quality of the coating according to the voltage used. 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.

2. Voltage

Electrophoretic coating adopts the constant voltage method, and the electrophoresis 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, the surface of aluminum and aluminum alloy can be 60～100V, and the surface of galvanized parts is 70～85V.

3. Paint temperature

The coating temperature is high, the film formation rate is fast, but the appearance of the paint film is rough, which will also cause the coating to deteriorate; the temperature is low, the amount of electrodeposition is small, the film formation is slow, and the coating film is thin and dense. During the construction process, as part of the electrical energy is converted into heat energy during electrodeposition, the mechanical friction in the circulation system generates heat, which will cause the temperature of the paint to rise. Generally, the temperature of the paint solution is controlled at 15～30℃ in some aspects

4. Paint resistance

The impurity ions brought by the coated object into the electrophoresis tank from the previous process cause a decrease in the resistance value of the paint, which leads to the appearance of roughness and unevenness of the paint film and pinholes. In the painting construction, the paint needs to be purified. In order to obtain high-quality coating film, anode blue equipment can be used to remove ammonium, calcium, magnesium and other impurity positive ions.