The influence of conductivity on electrophoretic coating

The influence of conductivity on electrophoretic coating:

1. To some extent, conductivity can determine the amount of paint applied to the workpiece.

2. Low conductivity will slightly reduce the deposition of cathodic electrophoretic paint, while high conductivity will slightly increase the deposition of cathodic electrophoretic paint.

3. If the conductivity of the tank solution is too high or too low, it will also affect the thickness, appearance, and permeability of the electrophoretic paint film, especially as the conductivity of the tank solution increases, the permeability also increases, resulting in a relatively thicker film thickness.

4. The abnormally high conductivity of the tank solution is often caused by high impurity content or low pH value, and is also accompanied by abnormal changes in coating quality, such as orange peel, pinholes, or severe re dissolution. Need to be managed through ultrafiltration and anode system.

The above content is about the influence of conductivity on cathodic electrophoretic paint. Generally speaking, it is advisable to control the conductivity within the range of 1200 ± 300 us/cm, as the conductivity is mainly maintained by ensuring the quality of deionized water before electrophoresis and updating the paint in the electrophoresis tank. Therefore, when the conductivity is too high, ultrafiltrate can also be discharged to adjust it.

The conductivity of cathodic electrophoretic coating solutions of different varieties also has a good control range. Based on small changes in conductivity, such as ± 100uS/cm, it will not affect the coating performance, so the control range is generally wide, at ± 30uS/cm. The high or low conductivity of the tank solution has an impact on the thickness, appearance, and permeability of the coating. As the conductivity of the tank solution increases, the permeability also increases, and the film thickness also increases relatively.

When the conductivity of the tank solution exceeds the upper limit of the specified value or is too high, deionized water can be used to replace the ultrafiltrate to reduce it. For example, replacing 20t of ultrafiltrate with deionized water for 300t of tank solution can reduce the conductivity of the tank solution by ± 100us/cm.