Usage of fluorescent dopants for high precision and three-dimensional temperature distribution measurement for verification of models and simulations in plastics welding

• Applicant: Professor Dr.-Ing. Martin Bastian
• Subject Area: Plastics Engineering ; Measurement Systems
• Term: from 2014 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 251578016

The usage of fluorescent dopants in polymers shall provide an opportunity to get a precise and spatially resolved temperature measurement on components during the welding process. The final goal of the developed method is to improve existing models and simulations for the welding process. Therefore, a three-dimensional spatially resolved temperature distribution in the region of the welded region is necessary. Currently no scientifically accepted and satisfactory ways allow the measurement of the temperature in the joining zone according to a three dimensional temperature resolution and without the direct influence of the welding process. The enormous potential through the use of temperature-sensitive fluorescent dopants for this purpose has already been successfully demonstrated in the application of a detailed temperature analysis in polymer melts during processing. Our preliminary investigations of solidified plastic samples confirmed the suitability of this method also for solid polymers. The incorporated dopants are only needed in the ppm range in the polymer and thus affect its physical and mechanical properties is negligible. The relationships between the fluorescence spectra of different dopants and polymers based on prevailing temperature should be investigated in this project in detail. Based on these dopants a measuring system shall be developed, which can provide new and as yet, less realizable measurement results with respect to the temperature distribution in the region of the joining zone during the welding process.

• DFG Programme: Research Grants