E-coat, electrocoat, or electrophoretic coating processes use charged particles to attract paint or coating particles or molecules in an immersion bath to the surface of a submerged part. E-coating is a dip coating process in which the coating or paint solids suspended in the bath are given an electrical charge, which is then attracted to the part. In a method closely paralleling electroplating, paint is deposited using direct electrical current. The electrochemical reactions that occur cause water-soluble resins to become insolubilized onto parts that are electrodes in the E-coating paint tank. Subsequent resin curing is required. E-coat processes are also referred to as electrocoating, electrodeposition, electronic coating, e-painting, electronic painting, electro coating, electrophoretic coat and electrophoresis coating.
Electrocoating, otherwise known as “E-Coat,” is a method of painting which uses electrical current to deposit the paint. The process works on the principal of “Opposites Attract” – materials with opposite electrical charges attract each other. In this system, electrodes in the coating tank create positively charged paint particles which are attracted to the negatively charged part. The paint particles are drawn to the metal part and paint is deposited on the part, forming an even, continuous film over every surface, in every crevice and corner, until the coating reaches the desired thickness. At that thickness, the film insulates the part, so attraction stops and electrocoating is complete.
C&E utilizes cathodic electrocoating, available in medium gloss black epoxy. In future we have also planned for acrylic black for more then 95% gloss & others colors lick white
Types of materials that can be Electrocoated.
Cold Rolled/Hot Rolled Steel, Galvanized Steel, Iron Castings, ZincCastings, Copper/Brass, Conductive Composites, Aluminum Extrusions and Castings, Rare Earth Magnets (NdFeB), NiZn Plated Steel, Stainless Steel, Chrome Plate.
Benefits of Electrocoating
• Environmentally friendly: Unlike most liquid coatings, there are no solvents to evaporate in the E-coat process. E-coat emits virtually no VOCs into the air, thus minimizing the impact on the environment. Also, any excess e-coat deposited or carried by the part is rinsed, reclaimed, and recycled to the electrocoat tank.
• Outstanding Performance: Electrocoating provides an extremely chemical and corrosion resistant finish. Depending on the application, it can be used as a single coat application or a base coat. Electrocoating also provides an exellent base for a variety of top coats. This “dual application advantage” creates a more decorative and durable finish.
• Adaptable for the most complex products: Electrocoating readily conforms to multifaceted configurations and yet maintains engineered tolerances on parts ensuring intended operating functions. Some examples include: internal surfaces, deep recesses, weldments, fasters, small parts, and large parts, all of which receive uniform coating (no sags or runs).
The Electrocoat process can be divided into four distinct zones:
The pretreatment zone cleans and zinc phosphates the metal to prepare the surface for electrocoating. Cleaning and zinc phosphating are essential to achieving the performance requirements desired by today’s end user of the product.
The Electrocoat bath is where the coating is applied. The electrocoat bath consists of 80-90% deionized water and 10-20% paint solids.The deionized water acts as the carrier for the paint solids which are under constant agitation. The solids consist of resin and pigment. Resin is the backbone of the final paint film and provides corrosion protection, durability, and toughness. Pigments are used to provide color and gloss.
The post rinses provide both quality and conservation. During the electrocoat process, paint is applied to a part at a certain film thickness, regulated by the amount of voltage applied. Once the coating reaches the desired film thickness, the part insulates and the coating process slows down. As the part exits the bath, paint solids cling to the surface and have to be rinsed off to maintain efficiency and aesthetics. The excess paint solids are called “drag out” or “cream coat.” These excess paint solids are returned to the tank to create a coating application efficiency above 95%.
The bake oven receives the parts after they exit the post rinses. The bake oven cross links and cures the paint film to assure maximum performance properties. Our typical bake cycles is 50 minutes at 200 degrees.