In-line fluorescence detector for production control in robot-driven environments

Fluorescence imaging is a powerful tool to detect the presence of processing agents, e.g., oils, lubricants, and organic coatings on metal surfaces. This imaging technique can be used in production, e.g. to determine the oil coverage on sheet metal to assure the best forming results or for inspecting the cleanliness of components before further processing like gluing, welding, coating, etc. The presented sensor is an evolution of the existing fluorescence laser scanner (F-Scanner) system1 and is optimized for measurement in motion. Adding this additional degree of freedom by mounting the scanner on a robot or gantry enables complete scans of large and complex shaped parts as well as selected areas that require special care, e.g., an increased level of cleanliness. The F-Scanner system has been improved in terms of footprint, weight, durability, and robustness. It can be operated with lightweight industrial robots and even cobots. In situations where ambient light makes fluorescence imaging challenging, a fast Fourier transform (FFT) based technique is used to ensure unperturbed measurements and high-contrast images. This work gives an overview of the advanced developments made and demonstrates the effect of FFT signal processing.