Dürr ESTA atomiser promises paint savings

Painting the interior of van and truck cargo spaces is a critical requirement for automakers. On passenger cars, a relatively small part of the interior is to be painted, since large areas of the surface will be covered later. In addition, these interior painting areas are situated favourably at the doors and hoods. In automated painting installations, robots open the doors and hoods. This way, the painting robots reach the designated surfaces without problems.

On vans and trucks, accessing the interior is not that easy for the painting robot. The quite long bodies often do not have any access or have only restricted access possibilities for painting robots on the sides. Only through the rear opening is it possible for robots to reach the whole interior.

Usually, air atomisers are used for the paint application but often the sprayed paint causes ’overspray’ leading to soiling in the booth. Today, air spraying processes are increasingly replaced by the ESTA process where the paint is sprayed with less kinetic energy. By means of charging the paint with high tension, the paint droplets follow the lines of electric flux to the grounded body. The transfer efficiency thus reaches 50 to 80 percent. Paint consumption and soiling are reduced and painting quality increased.

Dürr EcoBell2 atomisers are used for interior paint application with direct charging on vans and trucks. Two parallel lines are each equipped with one Dürr EcoRP8 painting robot with a swing arm. The bodies are conveyed into the waiting position of the interior painting zone on a skid in stop-and-go mode. After the preceding body has been fully coated, the robot swings from the painting position and clears the way for the waiting body. During this time, the purging and pre-painting process for the next colour is carried out along with any necessary atomiser cleaning with the fully automatic Dürr EcoBell Cleaner atomiser cleaning device. As soon as the body has reached the painting position, the robot swings into the painting position. With the travelling axis and the other movement axes of the robot, all necessary positions for the interior painting can be approached.

Essential parameters in the lines are the paint flow rates of 250-700ml (predominantly 400-600ml), the shaping air consumption of 350-600 Nl/min), the rotating speed of the atomiser with 50000 min-1, a constant high tension of 50 KV and a cycle time of 96 seconds. Compared to air atomisers, paint consumption can be lowered by 15 percent by the use of ESTA and the painting quality clearly improved.