Influence of printing material and printing ink layer on RFID antenna operation

Radio Frequency Identification (RFID) enables non-contact quick and easy data transferring through electromagnetic waves in the radio frequency range. The technology of RFID tags in the clothing and the textile industry is not commonly used yet, however, it enables the tracing of materials or textile products from their creation to sale, the identification of textiles and their protection against theft. In the research, the possibility of using of functional screen printing technique with an electrically conductive printing ink based on silver particles for the printing of passive RFID tags on textile material is showed. For printing, the two textile materials; polyester woven fabric, lyocell nonwoven textile and comparatively paper were used. The suitability of the selected textile materials for the printing of electronic structures for working passive UHF-RFID tags was tested. As a reference printing material that enables a high-quality print of electrically conductive structures, paper was used. The electrical conductivity of conductive patterns printed on textile materials and paper was measured, the quality of the prints and their abrasion resistance were assessed and the read range of the RFID tags on different printing materials was checked. It was found out that the best electrical conductivity of the prints was achieved on paper and slightly less electrically conductive prints were on the lyocell nonwoven textile. The RFID antennas printed on lyocell had the same range of operation, i.e. 150 cm from the receiving antenna of the reader, as the prints on paper. On the polyester fabric, it was not formed such an uniform layer of electrically conductive printing ink as on the lyocell nonwoven textile, therefore the prints on polyester were less electrically conductive and the printed RFID antennas operated at a shorter distance, only 60 cm from the receiving antenna of the reader. The abrasion resistance of the surfaces of printed RFID antennas was poor on all printing materials, because the ink transferred from the prints to the rubbed samples; the worst surface-resistant were prints on the lyocell

Development of tactile floor plan for the blind and the visually impaired by 3D printing technique

The aim of the research was to produce tactile floor plans for blind and visually impaired people for the use in the museum. For the production of tactile floor plans 3D printing technique was selected among three different techniques. 3D prints were made of white and colored ABS polymer materials. Development of different elements of tactile floor plans, as well as the problems and the solutions during 3D printing, are described in the paper

Effect of printing process parameters on the shape transformation capability of 3D printed structures

The aim of our research was to investigate and optimise the main 3D printing process parameters that directly or indirectly affect the shape transformation capability and to determine the optimal transformation conditions to achieve predicted extent, and accurate and reproducible transformations of 3D printed, shape-changing two-material structures based on PLA and TPU. The shape-changing structures were printed using the FDM technology. The influence of each printing parameter that affects the final printability of shape-changing structures is presented and studied. After optimising the 3D printing process parameters, the extent, accuracy and reproducibility of the shape transformation performance for four-layer structures were analysed. The shape transformation was performed in hot water at different activation temperatures. Through a careful selection of 3D printing process parameters and transformation conditions, the predicted extent, accuracy and good reproducibility of shape transformation for 3D printed structures were achieved. The accurate deposition of filaments in the layers was achieved by adjusting the printing speed, flow rate and cooling conditions of extruded filaments. The shape transformation capability of 3D printed structures with a defined shape and defined active segment dimensions was influenced by the relaxation of compressive and tensile residual stresses in deposited filaments in the printed layers of the active material and different activation temperatures of the transformation

Humidity Sensors Printed on Recycled Paper and Cardboard

Research, design, fabrication and results of various screen printed capacitive humidity sensors is presented in this paper. Two types of capacitive humidity sensors have been designed and fabricated via screen printing on recycled paper and cardboard, obtained from the regional paper and cardboard industry. As printing ink, commercially available silver nanoparticle-based conductive ink was used. A considerable amount of work has been devoted to the humidity measurement methods using paper as a dielectric material. Performances of different structures have been tested in a humidity chamber. Relative humidity in the chamber was varied in the range of 35%–80% relative humidity (RH) at a constant temperature of 23 °C. Parameters of interest were capacitance and conductance of each sensor material, as well as long term behaviour. Process reversibility has also been considered. The results obtained show a mainly logarithmic response of the paper sensors, with the only exception being cardboard-based sensors. Recycled paper-based sensors exhibit a change in value of three orders of magnitude, whereas cardboard-based sensors have a change in value of few 10s over the entire scope of relative humidity range (RH 35%–90%). Two different types of capacitor sensors have been investigated: lateral (comb) type sensors and modified, perforated flat plate type sensors. The objective of the present work was to identify the most important factors affecting the material performances with humidity, and to contribute to the development of a sensor system supported with a Radio Frequency Identification (RFID) chip directly on the material, for use in smart packaging applications. Therefore, the authors built a passive and a battery-supported wireless module based on SL900A smart sensory tag’s IC to achieve UHF-RFID functionality with data logging capability

Humidity Sensors Printed on Recycled Paper and Cardboard

Research, design, fabrication and results of various screen printed capacitive humidity sensors is presented in this paper. Two types of capacitive humidity sensors have been designed and fabricated via screen printing on recycled paper and cardboard, obtained from the regional paper and cardboard industry. As printing ink, commercially available silver nanoparticle-based conductive ink was used. A considerable amount of work has been devoted to the humidity measurement methods using paper as a dielectric material. Performances of different structures have been tested in a humidity chamber. Relative humidity in the chamber was varied in the range of 35%–80% relative humidity (RH) at a constant temperature of 23 °C. Parameters of interest were capacitance and conductance of each sensor material, as well as long term behaviour. Process reversibility has also been considered. The results obtained show a mainly logarithmic response of the paper sensors, with the only exception being cardboard-based sensors. Recycled paper-based sensors exhibit a change in value of three orders of magnitude, whereas cardboard-based sensors have a change in value of few 10s over the entire scope of relative humidity range (RH 35%–90%). Two different types of capacitor sensors have been investigated: lateral (comb) type sensors and modified, perforated flat plate type sensors. The objective of the present work was to identify the most important factors affecting the material performances with humidity, and to contribute to the development of a sensor system supported with a Radio Frequency Identification (RFID) chip directly on the material, for use in smart packaging applications. Therefore, the authors built a passive and a battery-supported wireless module based on SL900A smart sensory tag’s IC to achieve UHF-RFID functionality with data logging capability