The primary coating layer that inhibits salt spray induced corrosion on vehicle bodies is electrocoat. The application of electrocoat involves the electrodeposition of a polymer film on all metallic components of the vehicle body after body construction. Particularly challenging in the electrocoat process is the deposition of the coating in recessed areas of the vehicle due to material and electrical current access constraints to those regions. Currently the verification of correct electrocoat coverage requires the use of costly tear-down prototypes. A simulation tool, called EPD, has been developed that predicts the electrocoat coverage on the full vehicle body. The tool allows engineers to identify areas where there may be issues with electrocoat coverage and to see the effect of vehicle design or process modifications on coverage.
A challenge in the development of any simulation tool is computational speed. Because the electrocoat process can be simulated as a DC electric field problem, boundary element methods can be used, resulting in a significant reduction in the computational intensity of the simulation. In the paper, details of the physics-based tool – EPD – will be given as well as examples of practical use of the tool on vehicle parts, vehicle programs, and for electrocoat tank design. Benefits from the tool such as improved vehicle quality, paint usage reduction, energy reduction, and environmental savings will also be discussed.
