Schematic representation of 3D scanning with the SelfPaint booth, using a chair as an example.
Fraunhofer ITWM
Regardless of the industry, products are becoming increasingly customised, with "batch size 1" being the long-term goal. When it comes to the painting process, however, businesses still face major challenges since automation and customised paintwork have never proven readily compatible. Programming a painting robot to do the job is viable only when many identical components need to be spray-painted. This is often no longer the case today, however, so well over half of all components are painted by hand in many industries.
The self-programming SelfPaint booth is set to offer companies an alternative solution, making a wide range of savings possible. SelfPaint was developed by Fraunhofer Institute for Manufacturing Engineering and Automation IPA, as well as Fraunhofer Institute for Industrial Mathematics ITWM, in Germany, together with the Fraunhofer-Chalmers Research Centre for Industrial Mathematics FCC in Sweden. "Our SelfPaint technology enables the automated painting of small batches and even single pieces", says Dr. Oliver Tiedje, IPA group manager and coordinator of the project: "Thanks to this new technology, we save up to twenty percent in paint. This in turn reduces solvent emissions by twenty percent. What’s more, the booths consume fifteen percent less energy and complete the work five percent faster than conventional painting processes." A further benefit is that the automated process also outperforms manual painting operations in terms of reproducibility.
Automated painting is a five-step process. A component is scanned in 3D first. The scan data forms the basis for a fluid dynamic simulation: the relevant software simulates the trajectory of the paint particles and then determines the optimum volume of paint and air needed to achieve the required coating thickness. In the third step, the system uses the simulation data to determine the optimal robot path for the painting process. The painting process itself is then carried out. In the fifth and final step, the quality is checked. "For the quality control checks we apply terahertz technology, in other words a beam of light at a wavelength that lies between microwave and infrared. This enables us to measure wet, coloured paint without actually touching it", says Joachim Jonuscheit, deputy department head at Fraunhofer ITWM. The prototype is slated for completion in late 2018, and should help increase the degree of automation and flexibility of painting technology in production.