Punching Parts Gantry Self-Dipping Line

　　The impurity ions, such as those carried into the electrophoresis tank from the previous process step, can reduce the coating's electrical resistance, leading to defects like rough, uneven film surfaces and pinholes. Therefore, during coating application, it’s essential to purify the coating material thoroughly. To achieve high-quality coatings, cathodic shielding equipment can be used to remove impurity cations like ammonium, calcium, and magnesium.

　　Voltage-controlled electrophoretic coating uses a constant-voltage method, making the equipment relatively simple and easy to control. Voltage significantly influences the quality of the paint film: higher voltages result in thicker coatings, which can enhance coverage in hard-to-reach areas and reduce application time. However, excessively high voltage may lead to a rough film surface, increasing the likelihood of "orange peel" defects after baking. Conversely, too-low voltage slows down the electrochemical reaction, producing thin but evenly distributed coatings with poor penetration power. The appropriate voltage setting depends on factors such as the type of coating material and specific application requirements. Typically, voltage is inversely proportional to the solid content of the coating and the coating temperature, while it increases proportionally with the distance between electrodes. For steel surfaces, voltages range from 40 to 70V, whereas aluminum and aluminum alloy surfaces can accommodate slightly lower voltages.

　　Electrophoresis time directly influences coating thickness: as the electrophoresis time increases, the film thickness also grows. However, once the coating reaches a certain thickness, further extending the process won’t add more material—instead, it may even intensify unwanted side reactions. Conversely, if the electrophoresis time is too short, the resulting coating will be too thin. Therefore, electrophoresis time should be optimized based on the applied voltage, aiming for the shortest duration possible while still ensuring high-quality coatings. Typically, standard workpieces are electrophoresed for 1 to 3 minutes, while larger or more complex parts may require 3 to 4 minutes. For objects with intricately shaped surfaces, the voltage can be slightly increased, and the electrophoresis time extended accordingly to achieve uniform coverage.