BMW: A new level of individualization

It is true that sophisticated atomizer technologies and paint mist separation processes are succeeding in minimizing the consumption of resources for painting processes in the automotive sector. But much better than less overspray and filtered exhaust air is, of course, no overspray at all. Just a few years ago, a series production process with an overspray-free painting process seemed downright utopian. But as early as the end of 2020, a renowned Bavarian automobile manufacturer presented to the trade press the first series production process for an overspray-free applied contrast paint finish - with the EcoPaintJet from Dürr. However, this first generation required a start-up and run-down distance of several centimeters, which meant that selective applications in the center of a surface or even special patterns were not possible. For this purpose, the BMW Group, together with the machinery and equipment manufacturer Dürr, further developed the new application process with the EcoPaintJet Pro for processing the waterborne paints and the 2K clear coat. The new process does not require electrostatics and works with a jet application. Here, a nozzle plate forms fine paint jets that enable sharp-edged application with variable coating widths between one and around 50 millimeters.

Contrast coatings but also freely designed patterns

Both classic two-tone coatings such as a contrasting roof and the application of stripes and patterns are possible. In order to be able to guarantee sufficiently precise and, above all, reproducible transitions and movement patterns here, extreme precision is required in the robot and application technology, which goes far beyond what is necessary for conventional painting processes with a spray gun or high-rotation atomizer. The most important further development of the EcoPaintJet Pro is that the nozzles can be controlled individually, so that individual paint patterns are possible at almost any position on the car body. This means unimagined possibilities for displaying graphic elements on car bodies, even in series production. The BMW Group plant in Dingolfing has now tested the EcoPaintJet Pro, the latest overspray-free painting process, in a small series: The new application technology was used on 19 BMW M4 Coupés that rolled off the production line at the Dingolfing plant with an individual bicolor paint finish and M4 identification on the hood and tailgate. Since then, these vehicles have been undergoing practical trials. "We place the highest demands on our production in terms of efficiency, sustainability and digitalization," says Milan Nedeljkovic, Member of the Board of Management of BMW AG responsible for Production. "This smart painting technology combines all the requirements of an innovative production process and also offers unique customer benefits."

Minimization of workload and space and material requirements

Until now, multicolor coating could only be achieved by manual masking. With the new technology, the material and personnel required for this are no longer necessary, so that the implementation can be carried out at lower cost. The new process also prevents any overspray for this application step - an important contribution to more sustainable production. This is because if no coating separation is required, the air volumes needed for booth ventilation are reduced. With around 7,000 operating hours, this results in energy savings of more than 6,000 megawatt hours and a reduced CO2 footprint of almost 2,000 metric tons per year. BMW is continuing to develop the paint technology for further series applications. The one-offs from the M4 Coupé small series are being used in the company's vehicle fleet and tested for their suitability for everyday use. Further development of the process for vertical surfaces has also progressed. It is expected that in the future it will be possible to paint every component in the vehicle exterior using the new painting process and to offer customers individualization options with virtually no restrictions. It is not only the developers at Dürr who are convinced that painting without overspray will gradually establish itself in more and more applications in the future.

Author: CB

Pictures: BMW

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