Luminescence labeled surfaces mapping system dedicated for use in quality control of 3D prints produced by stereolithography 3D printing (SLA) and laser engraving

Compounds from the lanthanide complex family have been proposed as molecular luminescent sensors for marking and measuring objects. To select the sensor with optimal performance parameters, several series of Eu (III) complexes with diketone ligands were tested. This part of the work focuses primarily on examining the absorption and emission characteristics of the analyzed sensors in the UV-Vis range. Furthermore, the photostability of these sensors was tested during exposure to ultraviolet light. Based on the spectroscopic analysis, a compound showing high photostability, strong luminescence, and a wide absorption spectrum, reaching almost the range of visible light, was selected for marking 3D prints. Analysis of the obtained results of mapping the surface of luminescence-marked 3D inscriptions showed a strong impact of engraving parameters, such as laser power, laser beam collimator setting, space between symbols, and distance of the laser head from the print surface, on the quality of the obtained prints. The constructed measuring system allows accurate mapping of the surface of luminescence-labeled objects, particularly accurate mapping of the sample thickness in the direction normal to the camera lens, with micrometric resolution. One potential application of this apparatus is the quality control of prints produced using 3D printers based on photocurable resins or laser engraving. It is characterized by simple construction, low equipment cost, and short measurement time. Using an appropriate luminescent sensor to mark the tested objects, it is also possible to map the distribution of parameters such as temperature, pH, micro-viscosity, polarity, and oxygen concentration on its surface.