Similar to the electroplating of metal, electrocoating uses electrical attraction to draw paint to metal parts.
Use of electrocoating is growing rapidly as both a primer and finished coat due to its many productivity, quality and environmental benefits. Offering excellent transfer efficiency with little or no harmful air emissions, E-coat is becoming the technology of choice for many high-volume finishing operations.
E-coat is a relatively complex chemical and electrical process. In simple terms, it can be defined as the electrical deposition of a paint film on a conductive part. To form an E-coat film, a part is electrically grounded and immersed in a paint bath that has a charge of the opposite polarity. When current is applied, the resin and pigment in the bath separate from the solution and migrate to the part, where they form a uniform coating.
Two types of E-coat systems are used. In "cathodic" or "cationic" E-coat systems, the part being coated is the grounded cathode, and the other terminal is the positively charged anode. In an "anodic" system, the part being coated is the grounded anode, and the cathode is charged negatively. Cathodic systems are favored by industry today because they have certain inherent benefits and produce better color quality and corrosion resistance, although anodic systems are still used.
The E-coat process is extremely efficient, depositing a uniform coating on all surfaces that can be wetted by the solution and reached by electricity. E-coat provides good coverage in recessed areas that are difficult to coat with electrostatic spray methods due to the Faraday cage effect. When a sufficient film build is achieved, the …