Pigs in the paint shop

Plastic component supplier Rehau and BMW have both benefited from the latest paint line technology supplied by Eisenmann. And it’s based on a pigging system that enables rapid paint changes with little loss

Surface finishing is one of Eisenmann’s areas of expertise. Amongst its wide offering in this area the German company’s fully-automated paint lines provide carmakers and suppliers with state-of-the-art equipment designed to make workflow through the paint shop a painfree experience. Two companies to have recently benefited are BMW and polymer component provider Rehau.

The increase in plastic attachments to the car body, such as bumpers, rocker panels and side trims, means there is now greater attention given to the surface finishing of those plastics. Automotive supplier Rehau has converted its existing installations to state-of-the-art standards with the help of Eisenmann to ensure this quality is consistent.

VarioBell at Rehau
The workflow process of a plastics painting operation requires the installation of a very broad range of technologies. The Eisenmann installation at Rehau includes primer, basecoat and clearcoat applications. Depending on the application, work is carried out using 1K water-borne paint, 2K water-borne paint and 2K solvent paints.

One of the ways basecoat is applied is with the use of the Eisenmann VarioBell. Working with high-rotation atomizers not only reduces overspray but also improves the coating and improves deep action in workpieces with complicated shapes. Moreover, VarioBells are very well suited to the particularly efficient process of electrostatic application which, in the case of Rehau, is also used in the paint applications. The clearcoat booths at Rehau are equipped with three painting robots, two of which are fitted with ESTA and one with a gun. This combination was chosen to guarantee optimum paint application. Following a drying phase the painted plastic parts are ready for use at the OEM.

Robots on the inside
Eisenmann’s task at BMW’s plant in Dingolfing was to make two spray booths in the base and clearcoat area more efficient. The booths are part of a 14 year-old topcoat painting line and their job is interior body painting. Until the conversion by Eisenmann this work was done manually. The brief was to fully automate interior painting while guaranteeing painting standards to a consistently high level. The company also wanted to reduce paint consumption substantially. Fully-automatic interior body painting is achieved by the use of robots. Painting is carried out in the railtracking, this means that the robot moves on its 7th axis synchronously with the travelling car body and paints at the same time. Thanks to the use of an automatic position recognition system based on cameras, all tolerances or deviations occurring in the system are recognised and allowances made for them. As a result, not only can a substantial reduction in overspray be achieved but throughput can also be increased. To achieve this, an intelligent control system was needed which brings together and directs materials handling, application, railtracking and robots on the 7th axis. Eisenmann achieved this by including its VarioController.

Thanks to the interaction of the systems the applicator is optimally positioned towards the painting surface. The car body position is determined in driving operation and the painting programs adapted to changing conditions. This goes right down to the smallest detail: each individual component, from the tank cover to the door, is monitored to guarantee premium painting. The aim of optimum paint application is thus achieved while minimising overspray, even in such a sensitive area as interior body painting.