Extrusion-Based Fused Deposition Modeling for Printing Sensors and Electrodes: Materials, Process Parameters, and Applications

Integrating extrusion-based fused deposition modeling (FDM) with advancements in conductive thermoplastic materials is fostering innovation in the fabrication of sensors, electrodes, and printable electronics. This review presents an in-depth analysis of the advantages and disadvantages of FDM compared to other additive manufacturing (AM) techniques, focusing on its unique capacity to create functional components. Various materials, including host materials and conductive filaments, both commercial and custom-made, are examined for their suitability in conductive component fabrication. The impact of key process parameters, such as pre-printing settings, printing parameters (e.g., layer thickness, infill density and pattern, print speed, extrusion width, raster angle and orientation, and bed temperature), and post-printing settings on the performance of conductive filaments is also discussed. The review highlights the working principles and applications of different types of sensors printed using FDM, including strain, pressure, temperature, and acceleration sensors, the fabrication of electrodes for physiological and electrochemical monitoring, showcasing the potential of FDM to integrate multifunctional sensing capabilities in a single build. Finally, the review explores the future prospects of FDM in sensor and electrode manufacturing, identifying key challenges that need to be overcome to further enhance the technology's potential in advanced applications.