Cathodic electrocoating (KTL, also known as cathodic dip coating or e-coating) is an electrochemical process in which components are coated in a bath of electrically conductive, water-based dip paint using direct current. Coating thicknesses range from 15 to 50 µm, depending on the part geometry, the applied voltage and the coating time.
After coating, the paint deposited on the part is cured in a continuous oven at temperatures between 180 °C and 200 °C. The result is a solvent-free, corrosion-resistant, impact- and scratch-resistant surface. One of the strongest arguments for the KTL process is its exceptional cost-effectiveness.
KTL coating meets the specific corrosion protection requirements of car manufacturers. Thanks to its smooth, fine finish, it is also in demand in other areas of metalworking. It is particularly well suited to castings, stamped and formed parts, and complete welded assemblies. Coated materials range from bare or galvanised steel to aluminium.
Substrates are prepared for KTL coating by spray degreasing, rinsing, activation and zinc phosphating. For aluminium only, Metob also offers degreasing and etch passivation using Bonderite Alodine M-NT 2040 R2.
The maximum part size for our state-of-the-art KTL line is 3,000 mm in length, 1,400 mm in width and 1,600 mm in height.
KTL coatings provide excellent corrosion protection. The uniform paint film is also an ideal base for subsequent powder coating or liquid painting. A key characteristic of KTL coating is its high resistance to chemicals.
The workpieces are loaded manually onto part-specific racks and pretreated by spraying or immersion. The KTL coating itself is applied by immersion, with the lead-free black electrocoat paint being deposited cataphoretically onto the substrate. The paint is then cured in a hot-air oven.
Cathodic paint deposition – also known as ‘cataphoresis’ – takes place in a bath of water-based dip paint. Coating thicknesses between 15 and 50 µm can be precisely controlled via the current flow. Excess paint particles are removed from the workpiece in a multi-stage process. The paint is then melted and cured in a hot-air oven at 180 °C – 200 °C.
Since 2018, a state-of-the-art line has been available for the KTL coating of aluminium components, including etch passivation (Bonderite Alodine M-NT 2040 R2).
Would you like more information about our KTL coating service? Robert Bähr and his team will be happy to help:
Robert Bähr, Head of Sales
Röthenstraße 21, 96247 Michelau
Phone +49 9571 898 31
robert.baehr@metob.de
