Carbon infrared system saves time and effort in two-color painting

An innovative process for automotive painting enables Audi to produce two-tone contrasting paints with a significant reduction in process time, as only one paint pass is required and so the entire process saves time and money and is environmentally friendly. Part of the new concept is an infrared module from Heraeus Noblelight, which realizes the necessary partial intermediate drying. The infrared module follows the geometry of the car part and dries in a very targeted manner. This saves one drying cycle of the complete car through the oven and thus contributes to the energy efficiency of the new process.

Kleinostheim, 22. March 2021

The two color painting of a car

Two-tone roof painting of an Audi using carbon emitters from Heraeus Noblelight
Two-tone roof painting of an Audi using carbon emitters from Heraeus Noblelight

For two-color coatings, masking, pre-masking and fine masking as well as sanding of the areas to be coated and a second coating pass are necessary.

Following any cleaning that is now necessary, the contrasting applications can be applied and sealed with clearcoat. The body then passes through the dryer a second time, is unmasked and needs a final inspection.

This is very time-consuming and cost-intensive and, in addition to the high amount of work involved, also resulted in high material consumption due to the necessary films and adhesive tapes.

Overspray-free coating (OFLA technology)

Overspray-free painting (OFLA), which is being used in series production for the first time at Audi, revolutionizes this time- and material-intensive process.

After the base coat is applied, the roof is partially dried. The black contrast color is then applied to the body by an applicator directly integrated in the line without overspray. The roof contrast paint is applied by lining up individual stripes with sharp edges without overspray. This means that there is no need to mask off the bodywork.

Carbon emitters provide the new intermediate drying step

Intermediate drying of the basecoat before OFLA application is carried out with the aid of an infrared module containing carbon emitters arranged to follow the course of the roof height. In this way, the first coat of paint is efficiently and selectively dried only on the roof. This is followed by the application of the second paint component, and only then does the car body move into the convection oven. The IR drying can be switched on in cycle mode, because not every roof gets a contrast color. The contrast paint is applied at the customer's request. Carbon emitters can be switched on and off very quickly, so heat is applied in a targeted manner. So a contrast painted car does not have to go through the convection oven twice. In addition, the contrast-painted cars can be produced in-line with the single-color cars.

Roof drying of an Audi with the help of carbon emitters from Heraeus Noblelight