Fraunhofer IPA showcases new developments at PaintExpo 2024

"Our aim is to develop sustainable solutions for painting and coating surfaces. To this end, we are developing resource-saving, automated and digitally optimized solutions," explains Dr. Volker Wegmann from Fraunhofer IPA. For example, researchers at the institute have succeeded in producing color pigments based on food waste. The raw material for these products comes from crabs: chitosan can be extracted from their chitin shells, which are produced in large quantities when they are poached. The surfaces of the chitosan powder form stable compounds with various dyes, which can then be added to paints. "Painting technology is an energy- and resource-intensive industry. It is therefore important to become more resource-efficient. Bio-based raw materials such as the new colour pigments can help with this," emphasizes Wegmann. The second crucial issue is to minimize losses during painting and coating. Automation technology can make an important contribution here: "So far, this has not been fully exploited in painting technology because the programming effort for individual pieces and small series is too high," says IPA colleague Dr. Oliver Tiedje. However, studies at the IPA have shown that the programming of painting robots can be accelerated and simplified with the help of simulations: If the entire painting process is modelled and optimized in advance, time-consuming and resource-intensive test painting can be dispensed with. Losses can also be reduced through new painting techniques: Until now, paints have usually been sprayed on, which inevitably results in spray mist. This overspray means that some of the resources are lost. One alternative is the drop-on-demand technique developed at the IPA, in which paint is applied to surfaces drop by drop. This dripping saves material and eliminates process steps such as the protective covering of surfaces that are not to be painted, as well as time-consuming cleaning work. The new technology is the result of years of development work: various droplet application parameters and model paints were tested in numerous experimental and simulation trials as part of the "Digital Painting" project. Thanks to a simulation model, it was possible to work out the individual influences of paint, solvent, pigment and additive.

"Further opportunities for optimization arise from the use of digital data," adds Tiedje. "Although a lot of data is collected in paint stores, it is not used comprehensively. The use of innovative sensors, simulations and AI now enables new, efficient solutions." One example of the efficient use of data is a rheometer that digitally records the progression of paint layers during curing. The device works on a similar principle to the bat: it emits short ultrasonic calls of varying frequency, which are reflected by the environment depending on the surface condition. The innovative rheometer also uses different frequencies to sound out the material properties: A plate with holes in it moves back and forth on a layer of paint as it hardens. As the viscosity decreases during curing, the oscillation of the cover plate is slowed down and the force required increases as a result. By measuring these changes in vibration, a computer program can draw conclusions about the appearance of the painted surface. "This data can be used to determine the optimum conditions for painting - without time-consuming trial-and-error tests," explains Tiedje. Fraunhofer IPA will be presenting the topics of digitalization, automation and sustainability in lectures at Stand 1322 in Hall 1 at PaintExpo from 9 to 12 April 2024 at 10 a.m. (sustainability), 1 p.m. (digitalization) and 3 p.m. (automation).