Printed Sensing – Development, Manufacturing and Testing of Printed Pressure Sensor

Abstract

Purpose of this work was to design and manufacture a printed thin film piezoresistive surface pressure sensor for monitoring surface pressure in industrial application. Manufacturing a printed surface pressure sensor for industrial application requires understanding of application environment and requirements associated to sensor functionality and performance which are very challenging.

Academic research and literature regarding piezoresistive composite materials composition and properties were reviewed and commercially available functional materials for sensor manufacturing for given specifications were discussed. Also, commercially available force sensing solutions were reviewed and used as a reference. Once the suitable materials were selected for testing the screens for sensor manufacturing were designed and purchased and sensor prototypes were manufactured using screen printing and manual assembly methods.

Printed electronics is a relatively new but expanding field of electronics requiring multidisciplinary competences from electronics and mechanical engineering as well as from materials science, chemistry, and physics. Standards and design rules for circuit and sensor design using printed electronics are very limited and functionality of printed sensors rely heavily on the properties of used materials as well as manufacturing methods. The sensor design was derived based on best practises used for commercially available force sensors application and information from piezoresistive ink manufacturers and academic research. Different manufacturing methods were reviewed, and screen printing was selected as suitable manufacturing method. Screen printing screens were designed using available design rules for screen design.

As a result, the surface pressure sensor prototypes were manufactured for measuring the surface pressure in industrial application and to start evaluation of the application specific characteristics. Detailed characterization for sensors were not made in the context of this work but the sensors can be used to gain more understanding of the piezoresistive sensor functionality and properties in application specific operation. The data can be then used to take the sensor design and possible functional materials development further towards commercial application.