Award for research into overspray-free and selective painting technology

Scientists from Fraunhofer IPA won the Otto von Guericke Prize 2023 with their research work on "Determining the structure-property relationships of paints for application using overspray-free and selective painting technology".

Thomas Hess and Franz Balluff from the Coating Systems and Painting Technology department at the Fraunhofer Institute for Manufacturing Engineering and Automation (IPA) were awarded the Otto von Guericke Prize 2023 on November 15 in Berlin. The two scientists applied to the jury with their work on "Determining the structure-property relationships of paints for application using overspray-free and selective painting technology".

In the "DigitalPainting" research project, Hess and Balluff investigated paint properties for droplet generation and developed specifications for paints and nozzles. With their findings, overspray can be completely avoided. In addition, manual process steps such as protective covering (masking) become superfluous and paint booths become more compact and flexible.

Overspray is the part of the spray mist that does not land on the workpiece during painting. This means that more paint is used than is actually required to coat a surface. This results in complex cleaning work on the affected surface. In the worst case, the entire painted component has to be disposed of and the painting process repeated. One solution is to create individual droplets in the nozzles that apply the paint. However, the paint must meet special requirements for this. Hess and Balluff have now clarified what these are.

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"Our aim was to combine physics - from droplet formation and application to coating formation - with chemistry, i.e. the composition of the coating materials, and to develop a scientific foundation in the form of characteristic curves, coating property profiles, nozzle geometries and process parameters," summarizes Balluff. In numerous experimental and simulation tests, he and Hess tested different droplet application parameters and developed model coatings in which the various components varied in order to investigate their influence on droplet formation.

"We were able to transfer all of this together into a simulation model that allowed us to work out the individual influences of the coating, solvent, pigment and additive," says Hess. The result is a comprehensive toolbox for manufacturers of paints and application technology as well as for users in paint stores. "With this painting process, we can offer our customers new solutions and a high degree of customization - and of course, the whole thing is overspray-free," says Max Hertfelder from Industrielackiererei Hertfelder in Marbach am Neckar, who himself was involved in the "DigitalPainting" research project and uses the process in his company. "We need much less air circulation and extraction. Paint booths can be designed more compactly and flexibly due to reduced air supply requirements. This is also reflected very positively on the cost side," continues Hertfelder.

The "DigitalPainting" research project was coordinated by the Research Association for Pigments and Coatings (FPL). Its Managing Director, Michael Hilt, describes the project as a prototype for joint industrial research: "We are in a position to serve two fields of technology at the same time: painting technology on the one hand and paint production on the other." Combining this is not a matter of course. "In this way, we are creating the opportunity for small and medium-sized companies in these sectors to remain competitive in the future and sustainably maintain a colorful world," continued Hilt.

The Otto von Guericke Prize is awarded by the German Federation of Industrial Research Associations "Otto von Guericke" (AiF) in recognition of outstanding work in the field of joint industrial research for the benefit of small and medium-sized enterprises. The jury consists of members of the Scientific Council of the AiF. The Otto von Guericke Prize has been awarded since 1997 and is endowed with 10,000 euros. (OM-12/23)