Electrophoretic painting, as a surface treatment technology widely used in industries such as automobiles, home appliances, and hardware, is highly regarded for its excellent corrosion resistance, adhesion, and decorative properties. However, during the actual production process, various defects may occur in electrophoretic painting due to various factors, affecting product quality and appearance. There are many types of defects in electrophoretic painting, with complex causes, requiring comprehensive control from several links such as tank liquor management, process parameter optimization, pretreatment, and post-treatment. This article will analyze the main defects of electrophoretic painting and their causes in detail, and propose corresponding prevention and control measures.

　　Firstly, particles are one of the most common defects in electrophoretic painting, manifested as a rough surface of the paint film or the presence of visible hard particles. This is usually due to impurities or foreign matter in the tank liquor, or incomplete cleaning during the pretreatment process, leaving dust, oil stains, and other contaminants on the paint film. Or during the drying process, dust in the air adheres to the surface of the wet film. To prevent the generation of particles, it is necessary to regularly filter and replace the tank liquor to ensure its cleanliness, strengthen the cleaning and inspection of the pretreatment link to ensure that the workpiece surface is free of contamination, and improve the workshop environment to reduce the dust content in the air.

　　Secondly, shrinkage holes, also known as craters, refer to the phenomenon of local凹陷 on the surface of the paint film, usually caused by uneven surface tension of the coating. This may be due to the presence of oil污, silicone oil, and other low surface tension substances on the surface, or the imbalance of the binder ratio in the tank liquor, leading to abnormal fluidity of the coating. To prevent the generation of shrinkage holes, it is necessary to thoroughly clean the workpiece surface to ensure no oil污 residue, adjust the binder ratio of the tank liquor, and use coatings with good leveling properties, and control the construction viscosity and drying speed within an appropriate range.

　　Furthermore, insufficient adhesion will cause the paint film to fall off during use, affecting the product’s service life. This may be due to improper pretreatment, the presence of scale or oil污 on the surface, or incomplete washing after electrophoresis, leaving residual impurities that affect the adhesion of the paint film. Or the curing temperature or time is insufficient, resulting in incomplete cross-linking of the paint film. To improve adhesion, it is necessary to strengthen the pretreatment to ensure the surface is clean and free of scale, optimize the post-electrophoretic washing process to completely remove residues, and control the curing temperature and time to ensure sufficient cross-linking of the paint film.

　　Finally, uneven paint film color will also affect the consistency of the product’s appearance. This may be due to poor pigment dispersion or unstable content in the tank liquor, or fluctuations in voltage or time during the electrophoretic process. To prevent uneven color, it is necessary to regularly check the pigment content and dispersion of the tank liquor, make timely adjustments, and stabilize the electrophoretic process parameters to avoid voltage and time fluctuations.

　　In conclusion, there are many types of defects in electrophoretic painting, with complex causes, requiring comprehensive control from several links such as tank liquor management, process parameter optimization, pretreatment, and post-treatment. Through scientific management and refined operations, the occurrence of these defects can be effectively reduced or even avoided, thereby improving product quality and production efficiency. In the future, with the continuous progress of electrophoretic painting technology, the application of new materials and new processes will provide more possibilities for solving these defects and promote the application of electrophoretic painting in more fields. It is hoped that the analysis in this article can provide a reference for electrophoretic painting production and application enterprises, and help improve coating quality and production efficiency.