Evaluation of the Curing Process Effects on the TCR of Temperature Sensors Printed by Aerosol Jet Printing

Abstract

Temperature sensors have been widely developed to control the course of diseases, improve haptic feelings, and in multi-sensing systems to compensate for the output of other temperature-sensitive sensors. The use of additive manufacturing to produce resistive temperature detectors (RTDs) with reduced dimensions and bulkiness is attracting great interest. Among the relevant process parameters and design choices, the curing process must be considered. In this work, two different commercial metallic-based materials are cured at various temperatures to evaluate the differences in their microscopic and macroscopic behavior. The sensors were designed, developed, and evaluated for their temperature coefficient of resistance (TCR) at different curing temperatures using a programmable climatic chamber. A scanning electron microscope has been used to microscopically inspect the sensing structures with respect to the different curing temperatures. The results show insightful correlations between the macroscopic and microscopic behavior of the used inks as well as the performance of the sensors. In particular, increasing the curing temperature decreased the room-temperature resistance in all the samples by up to 70% and increased the sensitivity by up to 95%. These findings will help propose better processes as well as design choices for the development of printed resistive temperature sensors.