Electro-Deposition Coating is a method to extract coating film through coating particles with electric charge into coated materials with the opposite electric charge by the electrolysis of solution conducted by potential difference, when DC power is provided the coated material and paint tank of opposite electrodes in water-soluble paint solution. The loss of paint is little, and effective coating can be carried out on welded joints, corner areas, inside of the coated material and sharp edges, and high grade coating is available as well. In general, it is classified into Anion type and Cation type depending on the polarity of coated material, and currently Cation type is generally used for bottom coating. Elector-Deposition process consists of “Electro-deposition main tank – UF1 washing – UF2 washing – UF3 washing – Pure washing”.