04 Fakultät Energie-, Verfahrens- und Biotechnik
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/5
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Item Open Access Automatic joining of electrical components to smart textiles by ultrasonic soldering(2021) Micus, Sebastian; Haupt, Michael; Gresser, Götz T.A suitable connection method to automatically produce E-textiles does not exist. Ultrasonic soldering could be a good solution for that since it works with flux-free solder, which avoids embrittlement of the textile integrated wires. This article describes the detailed process of robot-assisted ultrasonic soldering of e-textiles to printed circuit boards (PCB). The aim is to understand the influencing factors affecting the connection and to determine the corresponding solder parameters. Various test methods are used to evaluate the samples, such as direct optical observation of the microstructure, a peeling tensile test, and a contact resistance measurement. The contact strength increases by reducing the operating temperature and the ultrasonic time. The lower operating temperature and the reduced ultrasonic time cause a more homogeneous metal structure with less defects improving the mechanical strength of the samples.Item Open Access Integrating electronics to textiles by ultrasonic welding for cable-driven applications for smart textiles(2021) Micus, Sebastian; Rostami, Sahar Golmohammadi; Haupt, Michael; Gresser, Götz T.; Meghrazi, Milad Alizadeh; Eskandarian, LadanThe connection between flexible textiles and stiff electronic components has always been structurally weak and a limiting factor in the establishment of smart textiles in our everyday life. This paper focuses on the formation of reliable connections between conductive textiles and conventional litz wires using ultrasonic welding. The paper offers a promising approach to solving this problem. The electrical and mechanical performance of the samples were investigated after 15 and 30 wash-and-dry cycles in a laundry machine. Here the contact resistances and their peeling strength were measured. Furthermore, their connection properties were analysed in microsections. The resistance of the joints increased more than 300%, because the silver-coated wires suffered under the laundry cycles. Meanwhile, the mechanical strength during the peeling test decreased by only about 20% after 15 cycles and remained the same after 30 cycles. The good results obtained in this study suggest that ultrasonic welding offers a useful approach to the connection of textile electronics to conductive wires and to the manufacture of smart textiles.Item Open Access Textile-based coils for inductive wireless power transmission(2021) Micus, Sebastian; Padani, Laura; Haupt, Michael; Gresser, Götz T.We developed and evaluated different textile-based inductive coils for near-field wireless power transmission. The technology uses electromagnetic induction for the contactless transfer of electrical energy. Therefore, we investigated various methods for the attachment of conductive materials on a textile-based material and the production of textile-based coils based on QI standard. Afterwards, the textile-based coils were examined and evaluated due to their specific quality characteristics. This happens by calculating the transmission quality and the maximum efficiency of the system which enables comparison of different coil systems and indicates the transmission efficiency of the systems.Item Open Access New flexible protective coating for printed smart textiles(2021) Bartsch, Valérie; Arnim, Volkmar von; Kuijpens, Sven; Haupt, Michael; Stegmaier, Thomas; Gresser, Götz T.In the field of food packaging, the addition of exfoliated layered silicates in polymers has been established to improve the polymers’ gas barrier properties. Using these polymers as coatings to protect smart textiles from oxidation and corrosion while maintaining their textile properties should significantly extend their lifetime and promote their market penetration. The aim of this study was to print new polymer dispersions containing layered silicates to protect screen-printed conductive structures, and to test the resulting samples. For this, appropriate printing parameters were determined by statistical design of experiments. According to these results, conductive structures were printed and protected with the selected coating. The abrasion resistance and the continuity of the protective layer of the printed samples were then measured. A continuous protective coating of approximately 70–80 µm thickness was applied on a conductive structure. The printed samples showed a very high resistance to abrasion (unchanged by 85,000 abrasion cycles) while remaining flexible and presenting a lower water vapor permeability (<2.5 g/m² d) than the coatings commonly used in the textile field.