The collective research project “PrESens” examines the manufacturability and integration of resistive sensors (strain, temperature) in industrial devices. In collaboration with several industry and university partners, the “PrESens” project will investigate the limits of digital printing technologies for polymers and coated metallic base bodies in combination with convective and photonic sintering methods for creating integrated resistive sensors. New processes in the field of multi-axis digital printing and sintering technologies should in the future enable printed resistive sensors to be manufactured individually and in a cost-effective manner directly at the measuring site. This project by the Räumliche Elektronische Baugruppen 3-D MID e.V. research association is being funded through the AiF (German Federation of Industrial Research Associations) within the scope of the Collective Industrial Research programme (IGF) of the Federal Ministry for Economic Affairs and Energy.

Resistive sensors in the form of strain gauges are usually used to measure strain or analyse stress. These consist of several layers – a backing, a metallic foil, and a cover. A thin polyimide (PI) film is usually used for the backing. The sensitive metallic foil (measuring grid), which takes the form of meander structures, is located on this. Nowadays, strain gauges are manufactured in a multi-step procedure involving lithography and etching processes and must be manually glued to the measuring object and connected to measuring systems by experienced specialists. The application of sensing structures via 3D-capable printing processes directly at the measuring site would eliminate the need for the adhesive layer and subsequent assembly steps. This would reduce the total number of production steps and the amount of material needed and would possibly improve accuracy. This means that sensing structures could be integrated directly on the workpiece during the production process.

The “PrESens” research project will systematically investigate and comprehensively evaluate the printability of different material combinations on polymeric and insulated metallic 2D substrate surfaces, thereby allowing conclusions to be made as to the limits of corresponding printing technologies. Subsequently, expedient material and printing technology combinations will be selected and sensors for strain and temperature will be produced as examples and evaluated in the form of demonstrators.  

In addition to evaluating different printing processes, research will be carried out into the requisite material systems (in particular those based on Cu, Ag, carbon, and conductive polymers), insights will be gained into material interactions, and the reliability of printed resistive sensors will be evaluated. At the end of the project, a guide will be drawn up for users on which procedure to choose according to the achievable properties (strain gauge or temperature sensor layout, target resistance, TCR, K factor).  

Project leader: Prof. Marcus Reichenberger

Researcher: Jewgeni Roudenko, M.Sc.

Contributors: Chair of Manufacturing Automation and Production Systematics, Friedrich-Alexander University of Erlangen-Nuremberg

Associated partners: 2E mechatronic; AHMT; ATN Automatisierungstechnik Niemeier; Bosch Rexroth; Horeich; Neotech AMT; peptech; Schaeffler; Seho; Sensodrive; Sentinum; Vierling Production; Vitesco Technologies; WIKA

Funded by: the Collective Industrial Research programme (IGF), project 09739

Dates: 1 October 2020 – 30 September 2022