Automotive Wheel Coating Line

Automotive wheel coating line is a high end solution for automotive components coating. Not only for its high requirement of quality but also for the involved techniques and the coating material itself. Shenzhen AFNT has helped multiple automotive factories for plant installation.

Wheel hubs are currently available in steel and aluminum alloy materials. While steel products are ideal choice for heavy trucks, aluminum production is best for various cars. Aluminum products is featured for light, good heat dissipation and easy maintenance.

Aluminum wheel hub coating line is composed by following standard sections for full setup: Pre-treatment (degreasing, rinsing, phosphating and passivating) -> base coat painting -> drying -> top coat painting -> drying -> varnish painting.

Based the different requirements from manufacturers, someone just require powdercoating after polishing treatment. However, such painting technique is not good for rust prevention and protection. Above standard process is applied by all leading wheel hub factories.

Pre-treatment Stage

Pre-degreasing and Degreasing
Pre-degreasing uses a low-concentration alkaline degreasing agent, applied by spraying or immersion, to initially remove most of the oil, grease, and other impurities from the wheel surface. This step is like giving the wheel a preliminary “clean-up,” preparing it for more thorough cleaning later.

Degreasing uses a higher concentration alkaline degreasing agent to further deeply clean the wheel surface, completely removing residual oil, mold release agents, etc., leaving the wheel surface in a very clean state, like giving the wheel a thorough “bath.”

Water Washing
After degreasing, some degreasing agent will remain on the wheel surface, requiring multiple water washes. Generally, spray washing is performed first to rinse away most of the residual degreasing agent with clean water; then immersion washing is performed, allowing the wheel to soak thoroughly in clean water to further remove residual impurities and ensure a clean, residue-free wheel surface.

Surface Conditioning
Surface conditioning involves forming a uniform layer of phosphate crystals on the wheel surface. This crystal layer is very fine and uniform, like covering the wheel surface with a layer of fine “velvet.” Its function is to provide a good foundation for subsequent phosphating treatment, making the phosphating film more uniform and dense, and enhancing the adhesion between the coating and the wheel substrate.

Pure Water Washing
After phosphating, some phosphating solution and other impurities will remain on the wheel surface. To ensure the quality of the electrophoretic coating, pure water washing is required. Pure water is water that has been specially treated to remove various ions and impurities.

Spray Coating
After all pretreatment properly processed, wheels are moved to painting booth area for coating application. Spray process are programmed according to selected coating materials, 1C1B /2C2B /3C1B options are popular choice as per technical requirements.

Drying and Curing
The wheel hub after coating is sent to a drying and curing oven. Under certain temperature and time conditions, the coating undergoes a curing reaction, forming a hard and durable coating. The temperature and time for drying and curing are adjusted according to the type of paint and process requirements. Generally, the temperature is between 160 and 190℃, and the time is about 20 to 40 minutes. After drying and curing, the coating can better exert its anti-corrosion and decorative properties.

Wheel coating line FAQ

What line structure is recommended?

Currently there’re two types structure available: hanging type and ground rail type. Ground rail type is for spray coating purpose while the hang conveyor is normally configured for pretreatment and e-coating purpose.

What kind of paint is recommended?

Solvent and water base paint are being produced on the market. While the solvent type is cheaper, it’s harmful to human and environment. Water base paint is a little expensive but safe to worker and environment. There’s no special treatment required for water base products thus it will greatly reduce the investment for waste treatment.

How much size is required for plant installation?

The wheel hub coating line is 100% custom design based your requirement. For full setup, the entire line takes ≥300㎡.  Definitely there’s more space needed for other service arrangement. Just contact us with your needs so we can do accurate calculation.

How long for coating line manufacturing?

Coating line can be ready within 1-3 months based the project requirement. Installation/testing could be done within 30 days.

Can you show us existing project?

We do have multiple porjects on record in both domestic and oversea factories. However, we have NDA signed with our clients. If there’s need for visiting, we need to check with customer for approvement.