E-Coating by BENSELER

Cathodic dip coating

Since 1985, BENSELER has been supplementing its range of surface coating services with e-coating or cathodic dip coating.

 Find out more about the advantages and benefits of the cathodic dip coating process below.

What is E-Coating?

Cathodic dip painting or cathodic dip coating is a painting process in which a metallic component is immersed in a water-dissolved paint with a low solids content. By applying a DC electric field between the object to be painted (cathode) and a counter electrode, a paint layer with a high solids content is achieved. After subsequent baking, a paint film with excellent anti-corrosion properties is formed. 

For BENSELER customers, cathodic dip painting is often the first choice as a primer for powder and wet paints, but also as a cost-effective, functional coating. The e-coating process is practically waste-free and very low in solvents due to the application and is therefore sustainable due to the system.

Characteristics of E-Coating at a glance:

The e-coating process meets many automotive industry specifications worldwide and is particularly suitable for steel, ferrous materials, cast iron, galvanized ferrous materials, aluminium and magnesium. The e-coating (cathodic dip coating) process produces a uniform, painted surface. The heavy metal-free coating system enables uniform layer thicknesses of 15 to 40 μm, depending on the version.

It is characterized by good handling properties. Thanks to the dipping process, the paint also reaches cavities and hard-to-reach areas on the component, which can be coated with sufficient coverage. E-coating therefore offers excellent corrosion protection.

Further advantages of cathodic dip coating are:

• Cost-effective corrosion protection coating
• Good chemical resistance, e.g. to brake fluid
• Environmentally friendly due to low VOC content, water-soluble
• Free of heavy metals
• Black, similar to RAL 9005
• Resource-saving production process
• Temperature-resistant (long-term exposure up to 120°C)
• E-coat is an ideal primer for different paint finishes (Electrostatic Powder Paint, Wet Paint)

E-Coating (cathodic dip coating) process sequence:

Find out more about the application requirements and the e-coating process below.

Requirements for an application with e-coat

Metallic components, especially steel and aluminum alloys, are suitable for e-coating. BENSELER has been able to build up a great deal of process expertise for magnesium alloys in recent years.

Pre-treatment and assembly

If necessary, the components to be processed are first provided with covers to ensure that areas without coating do not come into contact with paint. The parts are then placed on specially adapted fixtures that support the best possible coating. 

After being fed into the fully automated e-coating system, the parts first go through the cleaning process at BENSELER. Depending on the base material and parts, several degreasing stages, decapping, chrome-free conversion or zinc phosphating are used. The aim is to clean the surface free of grease and activate it so that the subsequent cathodic dip coating layer can be ideally deposited. The pre-treatment process lays the foundation for the characteristics of the finished e-coating and is therefore a particular focus at BENSELER.

Application by means of e-coating

Following pre-treatment, the parts are automatically transported to the e-coating area with the electrocoating and the associated rinsing stages. The actual film formation of the cathodic dip coating then takes place in the paint bath. Under the influence of electricity, the paint particles migrate to the component and form an even, non-slip film. Coated in this way, the parts are washed in several rinsing stages to remove any residue of the dissolved paint before they are cycled into the drying oven.

During the drying process, the paint film applied in the bath polymerizes, or to put it more simply: it hardens and thus forms its functional properties.

Removal and quality assurance 

After coating, the components are removed from the coating device. If covers have been attached to ensure paint-free areas, these are removed properly.
At BENSELER, all parts undergo a visual inspection after coating. Further quality checks are carried out according to the test plan before the parts are prepared for further processing, assembly and/or packaging.

Examples of e-coating applications

E-coating is used worldwide in many specifications in the automotive industry and other industries, such as the agricultural machinery industry or in mechanical engineering.

E-coatings have proven themselves in practice for the following reasons:

  • Very good handling behavior of the coating. Ultimately, this is another reason why e-coating (cathodic dip coating) is a standard for priming complex components such as vehicle bodies, doors, flaps and other add-on parts. Internal surfaces can often be coated with a layer of paint as long as they can be reached by the aqueous paint system and are sufficiently cathodic in the cathodic dip coating process. This is a unique feature of the coating: this is not possible with either conventional paints or electroplating systems.
  • Very good overcoatability with other paint systems: A large number of paint systems are available from BENSELER which, in combination with e-coat primers, meet high visual requirements but also enable functional characteristics for the components. E-Coating is often combined, for example, with selected powder coating layers for high corrosion requirements or for optical applications with high corrosion protection requirements.
  • E-coating is also used as a final layer for many applications, where the uniform layer formation and the corrosion protection, which is sufficient for many applications at comparatively low unit costs, is particularly appreciated.
production of e-coated parts

Additional Customer Services for e-coatings

In addition to coating, BENSELER offers you the following customer services:

  • Assembly processes: Depending on the customer's requirements, we can take over assembly processes after or before the e-coating (cathodic dip painting) process. This ranges from simple riveting and gluing processes to joining processes and rubber bearing assembly.
  • Laser-assisted cleaning and partial decoating with lasers: Here, areas can be selectively pre-cleaned or decoated after coating. This approach is often superior to conventional masking technology in terms of process costs.
  • We are happy to carry out seam seal automotive on flanged components, such as flaps, or the application of insulating mats, for example on doors. Gauge tests with straightening and specific tests can also be included in the process flow.

BENSELER's aim is to optimally integrate its own processes into the customer's value stream by adding further services. 

This saves you time and money! Please contact us if you have any special requirements.

Downloads

BENSELER technical information for e-coating

To ensure that the process is perfectly suited to your requirements, the BENSELER sales team will be happy to provide you with personal advice at any time.

These BENSELER locations offer this procedure:

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