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2015
Presentation
Titel
Additive manufacturing of electrical functionalities
Titel Supplements
Presented at the 1st International Symposium on Additive Manufacturing (ISAM), February 25 - 26, 2015, Dresden
Abstract
Transportation of electrical current in 3D paths is necessary in a wide range of applications from sensors to aircrafts. By using rapid manufacturing technologies such as printing and fast sintering processes conductive tracks can be generated to produce cost efficiently customized conductive tracks in small series with high resolution. Research at Fraunhofer IWS focuses on developing new and more flexible additive manufacturing processes adding electrical functionalities on 2D as well as 3D components. By combining of the robust dispenser printing with sintering processes based on laser, plasma or IR treatment enables the mass customization of components and, therefore, the viable production of batches of one. For dispenser printing screen printing pastes may be used as well as nanoparticle-based dispersions. Possible applications include electronics on foil or textile, integrated antennas or electronic shielding, and energy harvesting devices. Thermoelectric generators (TEGs) transform waste heat into electricity. Drawbacks of state-of-the-art materials are their low efficiency, limited availability or toxicity of the raw materials, and high costs. Polymer materials in combination with printing techniques offer the possibility to manufacture flexible generators from non-toxic and easy available raw materials. The operation temperature of these materials ranges from room temperature up to100 °C; small temperature gradients of 1 K can be used. The intrinsic conducting polymers PEDOT:PSS and PEDOT:tos are typical p-type materials. Beneath the low thermal conductivity, PEDOT has several advantages, such as its high electrical conductivity, good environmental stability and flexibility [1]. Both were modified to increase the Seebeck coefficient, the electrical conductivity, and hence the power factor of the material [2]. PEDOT:tos was synthetized under defined conditions and annealed to optimize the electrical conductivity and Seebeck coefficient. Poly[Kx(Ni-ett)] was synthesized and deployed as n-type polymer. Several designs of printed TEGs were developed and evaluated [3]. Beneath two vertical designs also the printing of p-type and n-type thermoelectric material into a non-woven substrate was studied. This enables the manufacturing of flexible TEGs in a continuous, automated process.