Electrophoretic Treatment Process Solutions

Background and Requirements

The automotive industry in my country is currently undergoing a period of rapid expansion; however, it simultaneously faces intense competition. Against this backdrop, traditional anti-corrosion processes are no longer adequate to withstand the complex operating environments to which vehicles are subjected. A host of issues—such as body rust and reduced vehicle service life—have compelled the market to demand increasingly rigorous standards for automotive anti-corrosion treatments. It is precisely within this context that the cathodic electrocoating process has gradually gained prominence. Compared to traditional anti-corrosion primer spraying techniques, cathodic electrocoating offers exceptional anti-corrosion performance, significantly enhancing vehicle durability and yielding particularly pronounced improvements in overall product quality.

Solution Overview

The cathodic electrophoretic deposition (EPD) process is a coating method in which a metal workpiece is immersed in an electrophoretic bath solution. Upon activation of the power supply, the electrochemical reactions induced by the electric field cause the coating material to uniformly precipitate and deposit onto the surface of the workpiece, forming a water-insoluble paint film. This constitutes an extremely complex electrochemical reaction process, comprising at least four distinct stages: electrophoresis, electrodeposition, electroosmosis, and electrolysis. To ensure the quality of the electrophoretic coating, pre-treatment processes—typically involving phosphating, silane treatment, or zirconizing—are customarily performed prior to the actual electrophoresis.

Tenglong Automotive operates a fully automated cathodic electrophoretic coating line. Once a vehicle body is suspended from an automated electric hoist, the equipment initiates an autonomous operational sequence. The workpiece proceeds successively through a series of stages—including pre-degreasing, degreasing, silane treatment, cathodic electrophoresis, curing, and forced cooling—before emerging from the line as a finished product. This automated production line minimizes manual intervention, thereby ensuring an exceptionally high level of consistency in the quality of the electrophoretic coating.

Value Advantages

1. Electrophoretic paint utilizes water as its solvent medium; it poses none of the flammability or explosion risks associated with spray paints, thereby ensuring a high level of safety.

2. The organic solvent content in electrophoretic paint is merely 1–3%; compared to traditional processes, this significantly reduces atmospheric pollution and environmental damage.

3. Electrophoretic coatings feature uniform thickness, strong adhesion, and superior corrosion resistance. A smooth, uniform paint film is achieved across all parts of the product—including internal cavities, edges, and weld seams—thereby resolving the challenge of achieving comprehensive corrosion protection that traditional processes often fail to address, and significantly extending the product's service life.

4. Paint utilization efficiency can reach as high as 99%, drastically minimizing resource waste and lowering costs.

5. The electrophoretic process involves automated coating application, resulting in a uniform finish and controllable product quality, while simultaneously enabling a substantial increase in labor efficiency.