EuroBlech 2018

••• 18••• Innovationen An engineer performs robotics-supported testing of steel sheets for mechanical properties (residual stresses) using micro- magnetic testing (3MA). Photo: Fraunhofer IZFP / Uwe Bellhäuser Testing within seconds Quality assurance during production: smart sensors for efficient processes A solution that allows fast, reliable, and automated characterization of materials and detection of defects has been developed by scientists from the the Fraunhofer IZFP in Saarbrücken. When quality testing uses time-consum- ing destructive test methods, it can re- sult in enormous costs due to damaging or destroying the products. And given that testing is restricted to random sampling, faults in pro- cesses are often not found until a large amount of scrap has already been produced. Consequently, nondestructive testing methods represent an alternative, and after appropriate adaptation processes, also a replacement for destructive methods for the long run. Nondestructive system The research scientists developed a robotics-supported sensor sys- tem that can rapidly and easily be integrated into production processes. The automated application of intelli- gent, nondestructive sensor systems is not only essential for ensuring optimum product quality in production, it is also indispensable for realizing current ma- chine learning concepts. The potential use of such systems will be demonstrat- ed in an exemplary case of robotics-sup- ported testing of press-hardened parts by means of Electromagnetic acous- tic transducer (EMAT) and Micromag- netic multiparameter, microstructure, and stress analysis (3MA). EMAT allows couplant-free testing of defects in sheet metal, while parallel application of 3MA makes quantitative material characteri- zation possible. The advantages of the robotics-based combination of the two sensors (3MA, EMAT) include rapid testing in mere seconds, determining and evaluating several relevant quality characteristics, as well as the nondestructive testing of sheet metal. “The combined sensor- based testing process allows early de- tection of mechanical properties, e. g., the residual stress and the hardness of steel, as well as defects like cracks or necking. This will save resources, reduce costs, and contribute to strengthening manufacturers’ competitive position,” explained Frank Leinenbach, develop- ment engineer at the Fraunhofer IZFP. The institute has decades of experience and expertise in combining and auto- mating nondestructive testing methods for production. The steel-producing and -processing industries need nondestruc- tive testing methods in quality assur- ance. Frequently relevant quality characteris- tics include hardness, case depth, strength, and residual stresses. In this context, nondestructive mi- cromagnetic testing methods are optimally suited for providing fast and reliable statements on the quality status of ferromagnetic materials. User-friendly learning curve “An inspection task that is being requested frequently is the moni- toring of heavy steel plates, and the related detection of localized increases in surface hardening,” explained Sargon Youssef, researcher and engineer at the Fraunhofer IZFP. These localized effects can be detected by means of micromagnetic measuring effects when the 3MA-X8 testing tech- nology developed at the Fraunhofer IZFP is applied. The specific strengths of the 3MA-X8 testing system lie in its user-friendly learning curve and calibra- tion, as well as in its variable and robust sensor design. A key point is the test sys- tem’s multi-channel real-time capability. Schematic layout of a rolling line for nondestructive testing of heavy plates Photo: Fraunhofer IZFP