Using simulations to produce perfect paintwork
Automated painting is a five-step process. First of all, the researchers use robust state-of-the art systems to produce a three-dimensional scan of the component. Data from this scan forms the basis for a fluid dynamic simulation: customized 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 plan the robot path for the painting process. The painting process itself is then carried out. In the fifth and final step, the quality of the paintwork is inspected to check that the required coating thickness been achieved. “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, colored paint without actually touching it,” says Joachim Jonuscheit, deputy department head at Fraunhofer ITWM. The idea is for this whole process to be automated in everyday painting operations: robots will scan, paint and check the quality of the paintwork – all without human intervention.
While researchers from Fraunhofer IPA are coordinating the project and focusing on both the painting technology and the simulation of paint particles close to the atomizer, their colleagues in Sweden are simulating particle behavior close to the work piece and working on the automated path planning. More specifically, they are calculating how the droplets of paint move through the air, where they lay down on the target object and the thickness of the resulting layer of paint. At Fraunhofer ITWM, researchers are pursuing the 3D scanning technology and measurement of the coating thickness for quality control purposes. The individual modules are already complete. Now, the researchers are working to combine the individual steps to form one fully automated process. Expected to be completed in late 2018, the finished prototype is set to help increase the degree of automation and flexibility of painting technology in production.