Immaculate: clean surfaces thanks to fluorescence measuring technology

Inspection of surface cleanliness

Cleanliness is a quality criteria for many industrial products. This applies to the product itself as well as to production plants, where sensitive products such as food or pharmaceuticals are manufactured. And it is of increasing importance in the automotive sector, too. This is due to modern, highly efficient joining technologies such as laser beam welding, laser soldering and bonding which occasionally are sensitive to contamination caused, for instance, by remaining drawing or parting agents.  

In many cases, immaculate and residue-free surfaces are crucial to the quality of modern products. Fraunhofer IPM develops measuring systems which detect impurities or defects on surfaces directly within production line. Our sensitive measuring systems allow a 100 percent control of surfaces of different sizes.

By applying procedures of optical purity control, Fraunhofer IPM inspects single components as well as production plants, e.g. in pharmaceutical and food industry. So far, contamination is analyzed via sampling. By using fluorescence analysis, our systems detect interfering contaminations such as detergents or microbiological substances automated.

Imaging fluorescence measurements make use of a straightforward principle: many substances used for materials processing or cleaning, such as oils, greases or residues from wet chemical cleaning agents fluoresce. With fluorescence measuring systems, these substances can be detected contact-free on surfaces of components or plants. The system functions on an imaging principle so that quantity and distribution of impurities can be localized easily. For component inspections, conclusions can be drawn about the cause of the contamination – e.g. when impurities frequently occur in the same position. Also possible is detection by imaging of fluorescence markers, namely substances that can be selectively bonded to substances in order to detect them with fluorescence measurement technology. Depending on the task, the systems are based on different technologies such as infrared spectroscopy, fluorescence spectroscopy and scattered light measurements.